Straddle electric vehicle

ABSTRACT

A straddle electric vehicle which rotates a drive wheel by driving power generated in an electric motor, comprises a battery unit which is an electric power supply; and a battery case for storing the battery unit; wherein the battery case includes a pair of first case member and second case member which are joined together such that the first case member and the second case member are horizontally separable from each other, and a parting line of the first case member and the second case member extends above a bottom wall of the battery case; and wherein the first case member and the second case member include a first flange section and a second flange section, respectively, which define the parting line, and are separably joined to each other in a state in which the first flange section and the second flange section are engaged with each other.

TECHNICAL FIELD

The present invention relates to a straddle electric vehicle such as anelectric motorcycle, which activates an electric motor by electric powersupplied from batteries to generate driving power for moving thestraddle electric vehicle.

BACKGROUND ART

In recent years, for example, for the purpose of environmentalconservation, an electric motorcycle including as a driving power sourcean electric motor which is activated by electric energy stored in abattery has been developed (see, e.g., Patent Literature 1). PatentLiterature 1 discloses a battery case including a casing which opens atone side and a lid member for closing an opening of the casing.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Laid-Open Patent Application    Publication No. 2003-267283

SUMMARY OF INVENTION Technical Problem

To allow the case to be easily incorporated into the straddle electricvehicle, the size of the case is preferably reduced to a smallestpossible degree. On the other hand, to achieve continued driving of thestraddle electric vehicle, the size of the battery is preferablyincreased to a greatest possible degree. If a gap between the inner wallof the case and the battery is merely reduced to achieve this, thebattery cannot be easily removably mounted to the case. In a case wherethe battery of a great size is used, the case is required to bear theheavy weight of the battery. Under the circumstances, it is difficult toachieve both of a reduction of the size of the case to a smallestpossible degree and a high stiffness of the case to bear the heavyweight of the battery.

Accordingly, an object of the present invention is to easily removablymount the battery of a greatest possible size to the case of a smallestpossible size, while improving a stiffness of the case.

Solution to Problem

The present invention has been developed to achieve the above describedobject. According to the present invention, there is provided a straddleelectric vehicle which rotates a drive wheel by driving power generatedin an electric motor, comprising: a battery unit which is an electricpower supply for the electric motor; and a battery case for storing thebattery unit; wherein the battery case includes a pair of first casemember and second case member which are joined together such that thefirst case member and the second case member are horizontally separablefrom each other, and a parting line of the first case member and thesecond case member extends above a bottom wall of the battery case; andwherein the first case member and the second case member include a firstflange section and a second flange section, respectively, which definethe parting line, and are separably joined to each other in a state inwhich the first flange section and the second flange section are engagedwith each other.

In accordance with this configuration, the battery case includes thepair of case members which are joined together. Because of this, evenwhen the battery unit is in close proximity to the inner wall of thebattery case in a state in which the battery unit is stored in thebattery case, the battery unit designed to have a largest possible sizecan be easily removably mounted to the battery case designed to have asmallest possible size. The battery case is dividable, for example, inthe rightward or leftward direction, or in the forward or rearwarddirection. In this structure, the joint surfaces of the pair of casemembers extend vertically, and the parting line extends above the bottomwall of the battery case. By engaging the flange sections of the casemembers with each other, the case members are joined together.Therefore, the stiffness of a region of the battery case which is in thevicinity of the parting line is improved, and the bottom wall on whichthe weight of the battery unit tends to be exerted is allowed to have ahigh stiffness.

One of the first flange section and the second flange section may beexposed outward of the battery case farther than the other of the firstflange section and the second flange section and may be oriented in adirection different from forward. The forward means a driving directionof the straddle electric vehicle moving ahead, and is forward from theperspective of the rider.

In accordance with this configuration, even when a gap is formed betweenthe first flange section and the second flange section, the gap isoriented in a direction different from forward. This makes it possibleto suitably prevent rain water or water splashed by wheels and movingrearward relative to the vehicle body from entering the battery case.

The straddle electric vehicle may comprise a battery fastening sectionfor fastening the battery unit to the battery case; and the batteryfastening section may be placed in an inner space of the battery case.

In accordance with this configuration, it is not necessary to form athrough-hole in the battery case, for fastening the battery unit to thebattery case. This makes it possible to suitably prevent rain water orwater splashed by the wheels from entering the battery case.

The straddle electric vehicle may comprise a case joining section forjoining the first case member to the second case member; and the casejoining section may be provided on an outer surface of the battery case.

In accordance with this configuration, it is not necessary to form athrough-hole for joining the pair of case members together, in a wallsurface defining the inner space of the battery case. This makes itpossible to suitably prevent rain water or water splashed by the wheelsfrom entering the battery case.

The first case member and the second case member may be joined togethersuch that the first case member and the second case member are separablefrom each other in a forward or rearward direction, the first casemember may be placed forward relative to the second case member, thefirst flange section may include an outward protruding portion whichprotrudes outward of the case farther than the remaining portion of thebattery case and a rearward protruding portion extending rearward fromthe outward protruding portion; and wherein the rearward protrudingportion may be located outward of the case relative to the second flangesection and may be oriented rearward.

In accordance with this configuration, even when a gap is formed betweenthe first flange section and the second flange section, the gap isoriented rearward. This makes it possible to suitably prevent rain wateror water splashed by the wheels and moving rearward relative to thevehicle body from entering the battery case.

The straddle electric vehicle may comprise an inside electric componentstored in the battery case; an outside electric component disposedoutside of the battery case; and an electric wire electricallyconnecting the battery unit or the inside electric component to theoutside electric component; and the electric wire may extend from a rearsurface of the battery case to the outside electric component.

In accordance with this configuration, even when a gap is formed betweenthe electric wire and the battery case, the gap is oriented rearward.This makes it possible to suitably prevent rain water or water splashedby the wheels and moving rearward relative to the vehicle body fromentering the battery case.

The battery case may have an upper lid which is removably attached on anupper portion thereof; and the inside electric component may be placedin an upper portion in an interior of the battery case.

In accordance with this configuration, maintenance of the insideelectric component can be easily carried out. Even when water enters thebattery case, it becomes possible to suitably prevent the insideelectric component from being immersed in the water, because the insideelectric component is located at an upper side that is distant from thelower portion of the case.

The straddle electric vehicle may comprise a front wheel and a rearwheel which are placed such that the battery case is interposed betweenthe front wheel and the rear wheel in a forward or rearward direction;and an exhaust fan for exhausting air from an interior of the batterycase; and the exhaust fan may be placed at an upper portion of thebattery case.

In accordance with this configuration, since the exhaust fan is placedon the upper portion of the battery case, a possibility that rain waterenters the battery case through the fan can be reduced, as compared to acase where the exhaust fan is placed at a lower side.

Advantageous Effects of Invention

As should be appreciated from the foregoing description, in accordancewith the present invention, the battery can be easily removably mountedto the case, while improving a stiffness of the battery case. The aboveand further objects and features of the invention will more fully beapparent from the following detailed description with accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a left side view of an electric motorcycle which is anexemplary straddle electric vehicle according to an embodiment of thepresent invention.

FIG. 2 is a block diagram showing electric components and electric wireswhich are connected to a battery unit and an inverter of FIG. 1.

FIG. 3 is a perspective view showing a state in which the electriccomponents and the electric wires are mounted to the battery unit ofFIG. 1, when viewed from forward, rightward and above.

FIG. 4 is a perspective view showing a battery case of FIG. 1, whenviewed from forward, rightward and above.

FIG. 5 is a perspective view showing a state in which an upper lid isdetached from the battery case of FIG. 4, when viewed from rearward,rightward and above.

FIG. 6 is a cross-sectional view of the battery case of FIG. 4, whenviewed from rightward.

FIG. 7 is a partial cross-sectional view of the battery case of FIG. 4,when viewed from above.

FIG. 8 is a partial cross-sectional view of the battery case of FIG. 4,when viewed from above.

FIG. 9 is a partial cross-sectional view of the battery case of FIG. 4,when viewed from above.

FIG. 10 is a bottom view of down frames and the battery case of FIG. 1.

FIG. 11 is a partial cross-sectional view of the down frames and thebattery case of FIG. 10, when viewed from forward.

FIG. 12 is a partial cross-sectional view of the down frame and thebattery case according to a modified example, when viewed from forward.

FIG. 13 is a partial cross-sectional view of the down frame and thebattery case according to another modified example, when viewed fromforward.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings. The stated directions arereferenced from the perspective of a rider riding in an electricmotorcycle which is an exemplary straddle electric vehicle. Throughoutthe drawings, the same or corresponding components are designated by thesame reference symbols and will not be described in repetition indetail.

(Overall Construction of Electric Motorcycle)

FIG. 1 is a left side view of an electric motorcycle 1 which is anexemplary straddle electric vehicle according to an embodiment of thepresent invention. As shown in FIG. 1, the electric motorcycle 1includes a front wheel 2 which is a driven wheel, a rear wheel 3 whichis a drive wheel, a vehicle body frame 4 which is disposed between thefront wheel 2 and the rear wheel 3, and an electric motor 5 mounted tothe vehicle body frame 4. The electric motorcycle 1 is not equipped withan internal combustion engine and is configured to rotate the rear wheel3 by driving power generated in the electric motor 5.

The front wheel 2 is rotatably mounted to the lower portion of a frontfork 6 extending substantially vertically such that it is inclined witha certain caster angle. A steering shaft 7 is coupled to the upperportion of the front fork 6, and a bar-type handle 8 is attached to theupper portion of the steering shaft 7. A right grip of the handle 8 isan accelerator grip (not shown) which is manipulated by the rider toadjust the driving power generated in the electric motor 5.

The vehicle body frame 4 includes a head pipe 11, a pair of right andleft and a pair of upper and lower main frames 12, a pair of right andleft down frames 13, a pair of right and left pivot frames 14, a pair ofright and left swing arms 15, and a seat frame 16. The head pipe 11supports the steering shaft 7 such that the steering shaft 7 isrotatable.

The main frame 12 includes a pair of right and left upper main framemembers 12 a, a pair of right and left lower main frame members 12 b,and truss frame members 12 c coupling the upper main frame members 12 ato the lower main frame members 12 b. The upper main frame members 12 aextend substantially in parallel with the lower main frame members 12 b,respectively. The upper main frame members 12 a and the lower main framemembers 12 b extend rearward from the head pipe 11 such that they areinclined slightly downward. Each of the upper main frame members 12 a isbent substantially downward at its rear end portion and joined to thecorresponding lower main frame member 12 b to form a unitary member.Each of the truss frame members 12 c couples the upper main frame member12 a to the lower main frame member 12 b at a position which is forwardrelative to a point where the upper main frame member 12 a and the lowermain frame member 12 b are joined together. This structure can improve astiffness of the overall main frames 12.

Each of the down frames 13 includes a vertical frame member 13 aextending substantially downward when viewed from the head pipe 11, anda lower frame member 13 b extending substantially horizontally andrearward from the lower end of the vertical frame member 13 a. Each ofthe pivot frames 14 is coupled to the rear end portion of the main frame12 and the rear end portion of the lower frame member 13 b. The swingarms 15 extend substantially in a forward or rearward direction. Each ofthe swing arms 15 is pivotally coupled at its front end portion to thepivot frame 14, and supports the rear wheel 3 by its rear end portionsuch that the rear wheel 3 is rotatable. The seat frame 16 extendsrearward such that it is inclined slightly upward, from the rear endportions of the upper main frame members 12 a and the upper end portionsof the pivot frames 14. The seat frame 16 supports a seat (not shown) onwhich the rider and a passenger is seated in the forward or rearwarddirection.

The electric motor 5 is placed in a region which is below the downframes 13 and forward relative to the pivot frames 14. The driving powergenerated in the electric motor 5 is transmitted to the rear wheel 3 viaa driving power transmission mechanism 17. The electric motor 5 isstored into a motor case 18. The motor case 18 contains a transmission17 a (see FIG. 2) constituting the driving power transmission mechanism17, together with the electric motor 5 and is suspended from the downframes 12 and the pivot frames 14. It should be noted that thetransmission 17 a (see FIG. 2) may be a multi-stage transmission orgearless transmission, and may be manual or automatic transmission.

The electric motorcycle 1 incorporates an inverter case 19 and a batterycase 80. The inverter case 19 contains electric components including theinverter 20, while the battery case 80 contains electric componentsincluding a battery unit 60. The inverter case 19 is placed in a spaceof a substantially-inverted-triangle shape when viewed from a side,which is surrounded by the main frame 12, the pivot frame 14 and theseat frame 16, and positioned immediately rearward relative to the lowerrear end portion of the battery case 80.

The battery case 80 is placed in a space which is between the pair ofright and left main frames 12, above the lower frame members 13 b andforward relative to the pivot frames 14. The battery case 80 issandwiched between the front wheel 2 and the rear wheel 3 in the forwardor rearward direction. The battery case 80 is placed between the pair ofright and left main frames 12 such that it does not overlap with themain frames 12 when viewed from above. Therefore, by inserting thebattery case 80 into a space between the main frames 12, from above orfrom below, the battery case 80 can be mounted to the vehicle body frame4. As will be described in detail later, the battery case 80 issupported by the upper surfaces of the lower frame members 13 b, and thedown frames 13 serve as support frame members for supporting the batterycase 80 and the battery unit 60. Also, the battery case 80 is fastenedto the right and left main frames 12. This makes it possible toeffectively prevent an excess load from being applied to the down frames13, and support the battery case 80 with a heavy weight by the entirevehicle body frame 4.

As will be described later in detail, the front surface of the batterycase 80 is offset rearward in a stepwise manner, in an upward direction.This makes it possible to prevent interference between the handle 8 anda portion of the battery case 80 which portion is located above the mainframes 12. In addition, a portion of the battery case 80 which portionis located below the main frames 12, is increased in size in a forwarddirection to fill a dead space which is behind the front wheel 2, whichcontributes to an increase in a battery capacity. In the presentembodiment, each of the vertical frame members 13 a is joined to thefront end portion of the lower main frame member 12 b. Since the downframes 13 are not directly joined to the head pipe 11, it becomes easyto ensure the space in which the battery case 80 is placed, even if thecaster angle is set smaller. Also, the lower portion of the rear surfaceof the battery case 80 is offset forward relative to the upper portionof the rear surface. This makes it possible to prevent interferencebetween the rear portion of the battery case 80 and the rear endportions of the upper and lower main frame members 12 a, 12 b. Inaddition, a portion of the battery case 80 which portion is locatedabove the main frames 12, is increased in size in a rearward direction,which contributes to an increase in the battery capacity.

To steer the electric motorcycle 1, the rider is seated over the seat(not shown), stretches the rider's hands up to the handle 8, andstretches the rider's feet to the lower end portions of the pivot frames14. At this time, the rider grips the rear upper portion of the batterycase 80 located forward relative to the seat, with knees. As will bedescribed in detail later, the battery case 80 has a shape in which adimension of its rear upper portion in the rightward or leftwarddirection is smaller than a dimension of its rear lower portion in therightward or leftward direction. This allows the rider to easily gripthe battery case 80 with the knees. In addition, the rear lower portionof the battery case 80, which is not reached by the rider's knees, canbe increased in size in the rightward or leftward direction, whichcontributes to an increase in the battery capacity.

An air-intake duct 21 is coupled to the front surface of the batterycase 80, while an air discharge duct 22 is coupled to the rear surfaceof the battery case 80. The air-intake duct 21 extends forward from thefront surface of the battery case 80. The air discharge duct 22 extendsdownward from the upper portion of the rear surface of the battery case80 and is coupled to the upper surface of the inverter case 19. Byproviding these ducts 21, 22, ram air from forward is taken into theair-intake cut 21, and sent to the interior of the battery case 80 viathe air-intake duct 21. Also, the air is discharged from the interior ofthe battery case 80 to the air discharge duct 22, and sent to theinterior of the inverter case 19 via the air discharge duct 22. In thisway, the electric components stored in the battery case 80 and theelectric components stored in the inverter case 19 can be cooled by theair. As a result, reliability of the operation of these electriccomponents can be maintained.

An air-intake port 21 a which is the upstream end of the air-intake duct21 protrudes forward farther than the axis of the front fork 6 whenviewed from a side. This makes it possible to prevent a situation inwhich rain water and mud splashed up by the wheels 2, 3 enters theair-intake duct 21 through the air-intake port 21 a. The downstream endof the air-intake duct 21 is connected to a portion of the front surfaceof the battery case 80, which portion is in the vicinity of the headpipe 11 in the forward or rearward direction, and overlaps with the mainframe 12 when viewed from a side. Because of this, the length of theair-intake duct 21 can be reduced significantly, in the layout in whichthe air-intake port 21 a is located forward relative to the front fork6. This can significantly reduce a passage resistance in the air-intakeduct 21, which allows the ram air to be sent smoothly to the interior ofthe battery case 80. Since the exhaust fan 22 is placed at the upperportion of the battery case 80, it becomes possible to reduce apossibility that the rain water or the like enters the interior of thebattery case 80 via the exhaust fan 22.

(Electric Configuration)

FIG. 2 is a block diagram showing the electric components and electricwires which are connected to the battery unit 60 and the inverter 20 ofFIG. 1. As shown in FIG. 2, the battery unit 60 includes a plurality ofbattery modules 61 and a battery frame 64. Each of the battery modules61 includes a plurality of battery cells 62 and a module casing 63 of arectangular parallelepiped shape, for storing the plurality of batterycells 62. Each of the battery cells 62 is a secondary battery which iscapable of storing DC power, and is, for example, a lithium ion batteryor nickel metal hydride. The plurality of battery cells 62 are alignedand electrically connected to each other in the interior of the modulecasing 63. The plurality of battery modules 61 are densely arranged inthe interior of the battery case 80 and electrically connected inseries, in a state in which they are connected to and fastened to thebattery frame 64. Although the plurality of battery modules 61 areillustrated as arranged laterally on the battery frame 64 of a trayshape in FIG. 2, specific layout of the battery modules 61 and specificstructure of the battery frame 64 are different from those shown in FIG.2, as will be described later (see FIGS. 3 and 6).

As should be understood from above, the battery unit 60 is configuredsuch that many battery cells 62 are connected in series in an electricview point, and as a result serves as the secondary battery ofhigh-voltage DC power (e.g., 200 to 300V). It should be noted that allof the battery cells 62 constituting the battery unit 60 need not beconnected in series. Alternatively, all of the battery cells 62 may bedivided into a plurality of groups, the plurality of battery cells ineach group may be connected in series, and the plurality of groups maybe connected in parallel.

The battery unit 60 is electrically and mechanically connected to theinverter 20 via a high-voltage electric wire 31 composed of a power wire31 p and a ground wire 31 n. The inverter 20 converts high-voltage DCpower supplied from the battery unit 60 into three-phase AC power. Then,the AC power is supplied to the electric motor 5 via AC wires 32. Theelectric motor 5 is activated by the AC power supplied from the inverter20 and generates the driving power corresponding to electriccharacteristics such as a current.

The power wire 31 p of the high-voltage electric wire 31 is connected inparallel with a bypass wire 33. A current steering resistor 34 and ananti-rush-current relay 35 are provided in series on the bypass wire 33.An inverter P-side relay 36 is provided on the power wire 31 p of thehigh-voltage electric wire 31, at a position between two connectionpoints at which the power wire 31 p is connected to the bypass wire 33.An inverter N-side relay 37 is provided on the ground wire 31 n of thehigh-voltage electric wire 31. The inverter case 19 contains a smoothingcapacitor 38 provided between the power wire 31 p and the ground wire 31n. When the vehicle is started, it becomes possible to prevent a rushcurrent with an excessively great magnitude from flowing through theinverter 20 by suitably selecting ON/OFF of the relays 35 to 37, evenunder a state in which charges are not accumulated in the smoothingcapacitor 38. Current meter(s) 53 is/are attached onto the power wire 31p, the ground wire 31 n and/or the bypass wire 33 (in FIG. 2, a casewhere the current meter 53 is attached only on the power wire 31 p isexemplarily shown).

A service plug 40 is provided on a wire 39 connecting the batterymodules 61 to each other. The service plug 40 includes a plug 41 forswitching between continuity (conduction) and cut-off of the wire 39 anda fuse 42 for cutting off the wire 39 if a current with an excessivelygreat magnitude flows therethrough. A maintenance operator operates theplug 41 manually to enable switching between a power supply state inwhich the wire 39 is placed in a conductive state and the electric powercan be supplied from the battery unit 60 to the electric motor 5 and acut-off state in which the wire 39 is placed in a cut-off state and theelectric power supplied from the battery unit 60 to the electric motor 5is cut off.

The electric motor 1 includes a low-voltage battery 43 which is asecondary battery of a low-voltage DC power (e.g., 12V), separately fromthe battery unit 60 which is a power supply for the electric motor 5.The low-voltage battery 43 is connected to a power load which is otherthan the electric motor 5, via a low-voltage electric wire 44. The powerloads which use the low-voltage battery 43 as the power supply include,for example, the exhaust fan 55 and an indoor fan 56 for generating anair flow in the interior of the battery case 80, a fan controller 57 forcontrolling the operation of the exhaust fan 55 and the operation of theindoor fan 56, a battery monitoring unit 58 for monitoring a state ofcharge (SOC) of the battery unit 60 and a vehicle control unit 59 forcontrolling the operation of the electric motor 5. In addition to these,the power loads include a lighting device such as a head light, a taillamp and a direction indicator, gauges or display device such as a speedmeter.

The low-voltage battery 43 is connected to a DC/DC converter 45 via afirst converter wire 46 composed of a power wire 46 p and a ground wire46 n. The DC/DC converter 45 is connected to the high-voltage electricwire 31 via a second converter wire 47 composed of a power wire 47 p anda ground wire 47 n. A DC/DC converter relay 48 is provided on the powerwire 47 p or the ground wire 47 n (in FIG. 2, a case where the DC/DCconverter relay 48 is provided on the ground wire 47 n is exemplarilyshown).

The high-voltage electric wire 31 is connected to a charging connector49 via a charging wire 50 including a power wire 50 p and a ground wire50 n. A charging P-side relay 51 is provided on the power wire 50 p,while a charging N-side relay 52 is provided on the ground wire 50 n.The charging connector 49 is connectable to an outside electric powersupply. When the charging connector 49 is connected to the outsideelectric power supply, the electric power is supplied from the outsideelectric power supply to the battery unit 60 via the charging wire 50and the high-voltage electric wire 31, thereby charging the battery unit60. Also, the low-voltage battery 43 can be charged with the electricpower supplied from the outside electric power supply. Or, duringdeceleration of the vehicle, the electric motor 5 operates as agenerator. In this case, the inverter 20 converts the AC power generatedin the electric motor 5 into the DC power, which charges the batteryunit 60 and the low-voltage battery 43. Also, the DC/DC converter 45converts the electric potential of the DC power stored in the batteryunit 60, and the DC power with the converted electric potential cancharge the low-voltage battery 43.

As described above, the plurality of electric components and theplurality of electric wires are connected to the battery unit 60 and theinverter 20. Among the plurality of electric components, the resistor34, the relays 35 to 37, 48, 51, 52, the service plug 40, the DC/DCconverter 45, and the current meter 53 are stored in the battery case80. The charging connector 49 may be stored into the battery case 80. Inaddition to the components shown in FIG. 2, a ground leakage detector 54(see FIG. 3) may be stored into the battery case 80. In descriptionbelow, in some cases, among the plurality of electric components, theelectric components stored into the battery case 80 will be collectivelyreferred to as “inside electric components 30”, while the electriccomponents (e.g., smoothing capacitor 38, the low-voltage battery 43,etc.) placed outside of the battery case 80, will be collectivelyreferred to as “outside electric components”. Among the plurality ofelectric wires, a portion of the high-voltage electric wire 31, theentire bypass wire 33, a portion of the first converter wire 46, theentire second converter wire 47, and the entire charging wire 50, arestored into the battery case 80.

(Battery Unit)

FIG. 3 is a perspective view showing a state in which the insideelectric components 30 and the electric wires are mounted to the batteryunit 60 of FIG. 2, when viewed from forward, rightward and above. Asshown in FIG. 3, each of the battery modules 61 includes the modulecasing 63 of a rectangular parallelepiped shape, and the battery modules61 are densely arranged such that its height direction substantiallyconforms to the vertical direction, its widthwise directionsubstantially conforms to the right and leftward direction, and itslengthwise direction substantially conforms to the forward or rearwarddirection. When the plurality of battery modules 61 thus denselyarranged are viewed in a macroscopic manner, they include a lowersection 65 of a rectangular parallelepiped shape, and an upper section66 stacked on the lower section 65. The front surface of the lowersection 65 is offset rearward relative to the front surface of the uppersection 66. The rear surface of the upper section 66 is offset forwardrelative to the rear surface of the lower section 65. The left sidesurface and right side surface of the lower section 65 are substantiallycoplanar with the left side surface and right side surface of the uppersection 66 at its front portion, while the left side surface and rightside surface of the lower section 65 are offset at its rear portiontoward the center in the rightward or leftward direction, relative tothe left side surface and right side surface of the upper section 66.Because of this structure, the upper surface of the upper section 66 hasa substantially-T shape when viewed from above.

The battery frame 64 includes a bottom plate portion 67 supporting thebottom surface of the lower section 65, a pair of lower side coverportions 68 covering the left side surface and right side surface of thelower section 65, a lower front cover portion 69 covering the frontsurface of the lower section 65, a lower rear cover portion 70 coveringthe rear surface of the lower section 65, an intermediate plate portion71 covering the upper surface of the lower section 65 and supporting thebottom surface of the upper section 66, a top plate portion 72 providedon the upper surface of the upper section 66, and a front bracket 63connecting the front edge of the top plate portion 72 to the front edgeof the intermediate plate portion 71.

The battery frame 64 is formed by joining together metal plate memberswhich are press-formed, by means of bolts. Each of the lower side coverportions 68 is fastened at its lower end portion to the bottom plateportion 67, and at its upper end portion to the intermediate plateportion 71. The lower front cover portion 69 is fastened at its upperend portion to the pair of lower side cover portions 68 and at its lowerend portion to the bottom plate portion 67. The lower rear cover portion70 is fastened at its upper end portion to the intermediate plateportion 71 and at its lower end portion to the bottom plate portion 67.The plurality of battery modules 61 are joined to the battery frame 64assembled as described above by means of bolts, etc., thus constructingthe battery unit 60.

By joining the battery modules 61 to the battery frame 64, the batterymodules 61 are unitarily coupled together. The battery frame 64 has aframe shape conforming to the outer shape of the battery unit 60, andhas a frame shape extending along the sides or surfaces of a cubic body,in the present embodiment. The battery frame 64 has a stiffnesssufficient to bear the weight of the battery modules 61 by its bottomsurface, in a state in which all of the battery modules 61 are joined tothe battery frame 64. In addition, the battery frame 64 is able tosupport the battery modules 61 even in a state in which it is suspendedby a suspending member attached on its upper surface.

In accordance with the battery unit 60 configured as described above,since the plurality of battery modules 61 are densely arranged such thatthe lower section 65 and the upper section 66 are stacked together inthe vertical direction, it becomes possible to suppress an increase inthe dimension of the battery unit 60 in the rightward or leftwarddirection while increasing the volume of the battery unit 60. Thisallows the battery unit 60 to be suitably incorporated into the electricmotorcycle including the vehicle body which is relatively small in therightward or leftward direction. The battery modules 61 are connected toand fastened to the battery frame 64. For this reason, the plurality ofbattery modules 61 restrict each other via the battery frame 64.Therefore, even if the battery unit 60 is subjected to loads such astwisting, bending, compression, tension and shear, during driving, itbecomes possible to suppress the battery modules 61 from being displacedindividually. As a result, a weight balance of the vehicle can bestabilized during driving.

In the present embodiment, to implement the above described shape of thebattery unit 60, the battery unit 60 includes two large battery modules61 a, one medium battery module 61 b, and four small battery modules 61c. The large battery modules 61 a, the medium battery module 61 b, andthe small battery modules 61 c are different in volume from each other.The two large battery modules 61 a are stacked together in the verticaldirection in a state in which they are not deviated from each other inthe forward or rearward direction or in the rightward or leftwarddirection.

The four small battery modules 61 c are placed such that they sandwichthe lower large battery module 61 a in the forward or rearwarddirection. The two small batteries 61 c at a front side are arranged inthe rightward or leftward direction, while the two small batteries 61 cat a rear side are also arranged in the rightward or leftward direction(in FIG. 3, only right side is shown). The large battery module 61 a andthe small battery modules 61 c are equal in height. This allows theupper surfaces of the five battery modules 61 at a lower side to besubstantially coplanar with each other and the bottom surfaces of thefive battery modules 61 at a lower side to be substantially coplanarwith each other. The width of the small battery modules 61 c is slightlysmaller than a half of the width of the large battery module 61 a. Thisallows the left side surfaces of the five battery modules 61 at a lowerside to be substantially coplanar with each other and the right sidesurfaces of the five battery modules 61 at a lower side to besubstantially coplanar with each other. In this way, the five batterymodules 61 constitute the above stated lower section 65.

One medium battery module 61 b is placed rearward relative to the upperlarge battery module 61 a. In other words, one medium battery module 61b is placed on the two small battery modules 61 c at a rear side. Themedium battery module 61 b and the large battery module 61 a are equalin height. This allows the upper surfaces of the two battery modules 61at an upper side to be substantially coplanar with each other and thebottom surfaces of the two battery modules 61 at an upper side to besubstantially coplanar with each other. The width of the medium batterymodule 61 b is smaller than the width of the large battery module 61 a.The widthwise center axis of the medium battery module 61 bsubstantially conforms to the widthwise center axis of the large batterymodule 61 a. This allows the left side surface and right side surface ofthe medium battery module 61 b to be offset toward the center in therightward or leftward direction, relative to the left side surface andright side surface of the large battery module 61 a. The upper surfaceof the medium battery module 61 b and the upper surface of the largebattery module 61 a have a substantially-T shape as a whole when viewedfrom above. The lengthwise length of the medium battery module 61 b isgreater than the lengthwise length of the small battery module 61 c.This allows the rear surface of the medium battery module 61 b to beoffset rearward relative to the rear surfaces of the two small batterymodules 61 c at a rear side. No battery module is placed forwardrelative to the large battery module 61 a at an upper side. This allowsthe front surface of the large battery module 61 a at an upper side tobe offset rearward relative to the front surfaces of the two smallbattery modules 61 c at a front side. In this way, the two batterymodules 61 constitute the above stated upper section 66.

It should be noted that the above described configuration is merelyexemplary, and the sizes of the battery modules 61 and the number of thebattery modules 61 can be suitably changed.

(Electric Components and Electric Wires Inside of Battery Case)

The battery unit 60 is assembled and integrated with the inside electriccomponents 30 and the plurality of electric wires, which are describedabove, and stored into the battery case 80 (see FIGS. 4 to 6). Since thebattery unit 60 has a high stiffness because of the battery frame 64, itcan continue to stably support the inside electric components 30 and theelectric wires, even when the battery unit 60 is subjected to a loadduring driving. In description below, an assembly of the battery unit60, the inside electric components 30 and the electric wires, will bereferred to as “battery assembly 79”.

Among the inside electric components 30, the DC/DC converter 45 ismounted to the front surface of the upper section 66. In front of thefront surface of the upper section 66, there is formed a space which canbe formed by offsetting the front surface of the lower section 65forward relative to the upper section 66. The DC/DC converter 45 isplaced in this space. The DC/DC converter 45 is in a lowest possibleposition within the space. The bottom portion of the DC/DC converter 45is in close proximity to the front edge of the intermediate plateportion 71 of the battery frame 64 and the upper surface of the uppersection 66. This makes it possible to avoid that a considerable recessedportion which recedes rearward is formed between the front surface ofthe DC/DC converter 45 and the front surface of the lower section 65, inthe vertical direction. Thus, the front surface of the battery assembly79 is offset rearward in a stepwise manner from a lower side toward anupper side. Since the dimension of the DC/DC converter 45 in the forwardor rearward direction is smaller than the lengthwise length of the smallbattery module 61 c, the front surface of the DC/DC converter 45 isplaced rearward relative to the front surface of the lower section 65.

Among the inside electric components 30, the resistor 34, the relays 35to 37, 48, 51, 52, the service plug 40, the charging connector 49, thecurrent meter 53, and the ground leakage detector 54 are mounted to theupper surface of the battery unit 60 (i.e., the upper surface of theupper section 66 and/or the upper surface of the top plate portion 72).These inside electric components 30, other than the DC/DC converter 45,are densely arranged in a rectangular region when viewed from above,which may be virtually defined on the upper surface of the battery unit60. This rectangular region in the forward or rearward direction extendsover substantially the entire upper surface of the battery unit 60 inthe forward or rearward direction. This rectangular region in therightward or leftward direction extends over substantially the entirewidth of the rear portion of the upper section 66 (i.e., medium batterymodule 61 b). In other words, the upper surface of the front portion ofthe upper section 66 (i.e., large battery module 61 a) constitutes apair of non-mounting surfaces 61 d in which the inside electriccomponents 30 are not placed, in a portion protruding in the rightwardor leftward direction, when viewed from the rear portion of the uppersection 66.

The relays 35 to 37, 48, 51, 52, are densely arranged in the rearportion of the rectangular region. The current meter 53 is adjacent tothe inverter P-side relay 36. The ground leakage detector 54 is placedin the front portion of the rectangular region. The service plug 40 andthe charging connector 49 are placed adjacently to the ground leakagedetector 54 in the rightward or leftward direction or between the relaygroup and the ground leakage detector 54 in the forward or rearwarddirection.

Among the relays 35 to 37, 48, 51, 52, the inverter P-side relay 36 andthe inverter N-side relay 37 are relatively large, while the remainingfour relays 35, 48, 51, 52 are relatively small. In view of this, theinverter P-side relay 36 and the inverter N-side relay 37 are arrangedside by side in the center portion in the rightward or leftwarddirection, in the rear portion of the rectangular region. The remainingfour relays 35, 48, 51, 52 are arranged such that the two relays 36, 37are sandwiched between the four relays 35, 48, 51, 52 in the rightwardor leftward direction. As will be described later, the exhaust fan 55(see FIG. 5) is attached to the rear upper portion of the battery case80 (see FIG. 5). The width of the exhaust fan 55 is smaller than thewidth of the relays 35 to 37, 48, 51, 52. The relays 35 to 37, 48, 51,52 are placed to face the exhaust fan 55 in the forward or rearwarddirection. In this structure, the relays 35 to 37, 48, 51, 52 can besuitably cooled by the air.

The electric wires stored in the battery case 80 are wire harnesses 74or bus bars 75. Each of the bus bars 75 includes a bent metal platemember 76 and an insulating cover 77 covering a portion between bothends of the metal plate member 76. The metal plate member 76 is placedto extend along the surface of the battery unit 60 and the surfaces ofthe inside electric components 30. A portion of the metal plate 76 whichis not covered with the insulating cover 77 serves as a contact which iselectrically connected to a terminal of the battery module 61 or aterminal of the inside electric component 30.

The buss bars 75 are used for electric connection accomplished inside ofthe battery case 80, while the wire harnesses 74 are used for electricconnection between the inside electric components 30 and the outsideelectric components. The electric connection accomplished inside of thebattery case 80 includes connection between the battery modules 61,connection between the inside electric components 30, and connectionbetween the battery modules 61 and the inside electric components 30.The high-voltage electric wire 31 (see FIG. 2) includes a portion usedfor the connection between the inside electric components 30 and aportion used for the connection between the inside electric components30 and the outside electric components. Therefore, the uses of the wireharnesses 74 and the uses of the bus bars 75 are easily understood whenan attention is paid to the power wire 31 p and the ground wire 31 nconstituting the high-voltage electric wire 31.

Regarding the power wire 31 p, the bus bar 75 is used in a portionconnecting the P terminal of the large battery module 61 a at an upperside to the inverter P-side relay 36. The bus bar 75 is also used in aportion connecting the inverter P-side relay 36 to the current meter 51.The bus bar 75 and the wire harness 74 are both used in a portionconnecting the current meter 53 which is the inside electric component30 to the smoothing capacitor 38 (see FIG. 2) or the inverter 20 (seeFIG. 2) which is the outside electric component. The bus bar 75 extendsfrom the current meter 53 and the wire harness 74 extends toward theoutside electric component. A terminal block 78 is provided on the rearend portion of the non-mounting surface 61 at a right side. The bus bar75 is electrically connected to the wire harness 74 at the terminalblock 78. The same applies to the ground wire 31 n. The bus bar 75 isused in a portion connecting the N terminal of the large battery module61 a at an upper side to the inverter N-side relay 37. The bus bar 75and the wire harness 74 are both used in a portion connecting theinverter N-side relay 37 which is the inside electric component 30 tothe smoothing capacitor 38 (see FIG. 2) or the inverter 20 (see FIG. 2)which is the outside electric component. The bus bar 75 extends from theinverter N-side relay 37 and the wire harness 74 extends toward theoutside electric component. The bus bar 75 is electrically connected tothe wire harness 74 at the terminal block 78 (see FIG. 5) provided onthe rear end portion of the non-mounting surface 61 d at a left side(see FIG. 5).

Two wire harnesses 74 used in the power wire 31 p and the ground wire 31n extend rearward from the non-mounting surface 61 d. These two wireharnesses 74 are apart outward in the rightward or leftward directionfrom the rear portion of the upper section 66. Also, these two wireharnesses 74 overlap with the upper surface of the rear portion of thelower section 65 (i.e., two small battery modules 61 c at a rear side).

Many of the electric wires connected to the battery unit 60 are placedto extend along the surface of the battery unit 60 and the surfaces ofthe inside electric components 30. This makes it possible to compactlyconfigure the structure in the vicinity of the inside electriccomponents 30. The wire harness 74 used in the high-voltage electricwire 31 is also placed in an outward region of the rectangular region inthe rightward or leftward direction and does not interfere with theinside electric components 30. If the metal plate member 76 is formed tohave a great width, it can easily have a greater cross-sectional areathan the wire harness 74, which makes it possible to reduce a need for amaterial which is expensive and has a great specific weight, such assilver and copper, although these have a high electric conductivity. Forexample, aluminum is suitably used as the metal plate member 76 to makethe electric wire inexpensive and light.

The anti-rush-current relay 35, the inverter P-side relay 36 and thecharging P-side relay 51 are connected in parallel to the power wire 31p. These relays 35, 36, 51 are placed in a rear right portion of theabove stated rectangular region. The relay 35 is relatively large insize, while the relays 36, 51 are relatively small in size. The heightof the relay 35 is different from the height of the relays 36, 51, butthese three relays 35, 36, 51 are placed such that their upper surfacesare coplanar with each other. Thereby, by merely mounting the flat busbar over the upper surfaces of these three relays 35, 36, 51, the abovestated parallel connection is implemented. Since these three relays 35,36, 51 are densely arranged, the flat bus bar can be reduced in size.The same applies to the inverter N-side relay 37, the charging N-siderelay 52 and the DC/DC converter relay 48 which are densely arranged ina rear left portion of the rectangular region.

(Schematic Configuration of Battery Case)

FIG. 4 is a perspective view showing the battery case 80 of FIG. 1, whenviewed from forward, rightward and above. FIG. 5 is a perspective viewshowing a state in which an upper lid 83 is detached from the batterycase 80 of FIG. 4, when viewed from rearward, rightward and above. InFIGS. 4 and 5, the air discharge duct 22 is not shown.

As shown in FIGS. 4 and 5, the battery case 80 includes a case body 81having an opening 82 at an upper portion thereof, and the upper lid 83which is detachably attached to the case body 81 and covers the opening82. With the upper lid 82 attached to the case body 81, a closed innerspace of the battery case 80 is formed. The battery unit 60 is storedinto the inner space of the battery case 80 in a state in which thebattery unit 60 is mounted to the electric components and the electricwires. The upper lid 83 is placed so as to overlap with the electriccomponents mounted to the upper surface of the battery unit 60, whenviewed from above.

By detaching the upper lid 83 from the case body 81, the inside electriccomponents 30 can be seen or accessed through the opening 82, fromoutside and above the battery case 80. Especially, the plug 41 of theservice plug 40 and the charging connector 49 are placed so as tooverlap with the upper lid 83, when viewed from above. Therefore, byopening the opening 82, the plug 41 and the charging connector 49 can beeasily accessed.

By pulling out the plug 41 upward, the maintenance operator can performswitching from the conductive state to the cut-off state in which theelectric power supplied from the battery unit 60 to the electric motor 5(see FIG. 2) is cut off. By returning the pulled-out plug 41 to itsinitial position, the maintenance operator can switch the cut-off stateto the power supply state in which the electric power can be suppliedfrom the battery unit 60 to the electric motor 5 (see FIG. 2). Thecharging connector 49 has an outlet 49 a into which a connector (notshown) of the outside electric power supply is inserted. The outlet 49 ais oriented upward. By inserting the connector of the outside electricpower supply into the outlet 49 a through the opening 82 from outsideand above, the rider can charge the battery unit 60. As should beappreciated from this, in accordance with the present embodiment, themanual operation and charging work of the service plug 40 can be carriedout easily. The bus bars 75 are used in many electric wires stored inthe battery case 80. Therefore, a situation will not happen, in whichthe manual operation and charging work of the service plug 40 becomemessy due to, for example, the fact that the plug 41 and the outlet 49 aare hidden by the presence of the wire harnesses when detaching theupper lid 83.

Alternatively, the charging connector 49 may be mounted to the side wallof the battery case 80 (see two-dotted line in FIG. 1). Even in thiscase, the entire charging wire 50 (see FIG. 2) can be stored into thebattery case 80, which is an advantage.

As shown in FIG. 3, a suspending member 84 which is a sheet metal of aninverted-U shape is firmly fastened to the top plate portion 72 of thebattery frame 64. When the battery case 80 storing the battery assembly79 is transported, a crane winch (not shown) is engaged with thesuspending member 84 in a state in which the upper lid 83 is detached.This allows the battery case 80 with the upper lid 83 detached to besuspended together with the battery assembly 79. In this way, thebattery case 80 with a heavy weight, incorporating the plurality ofbattery modules 61 (see FIG. 3), can be easily transported. Especially,by inserting the battery case 80 suspended by the suspending member 64into a space between the right and left main frames 12 from outside andabove the main frames 12, the battery case 80 can be mounted to thevehicle body frame 4. By attaching the upper lid 83 after the batterycase 80 is mounted to the vehicle body frame 4, the battery case 80having the closed space can be constructed. Alternatively, thesuspending member 84 may be attached to the side portion of the batteryframe 64 instead of the top plate portion 72.

(Shape of Battery Case)

The shape of the battery case 80 will be described with reference toFIGS. 3 to 5. The case body 81 of the battery case 80 has substantiallythe same outer shape as that of the battery assembly 79. Therefore, thecase body 81 does not have a precise rectangular parallelepiped shapebut has a shape in which several portions are recessed in a box of arectangular parallelepiped shape. The bottom wall of the case body 81 isa substantially flat plate. Since the upper surface of the upper lid 84attached to the case body 81 is also flat, it is possible to preventrain water from being accumulated on the battery case 80.

The lower portion of the rear wall of the case body 81 is offset forwardrelative to the upper portion of the rear wall of the case body 81. Thefront wall of the case body 81 is offset rearward in a stepwise manner,in an upward direction. This allows the inner surface of the batterycase 80 to be made close to the rear surface, front surface and uppersurface front portion of the lower section 65, the front surface andupper surface of the DC/DC converter 45, and the front surface of theupper section 66. As a result, the size of the case body 81 can bereduced to a smallest possible degree. As described above, it becomespossible to achieve both of prevention of interference between thebattery case 80 and the handle 8 (see FIG. 1) and an increase in thebattery capacity. In addition, it becomes possible to achieve both ofprevention of interference between the battery case 80 and the rear endportion of the main frames 12 (see FIG. 1) and an increase in thebattery capacity.

The width of the upper portion of the rear wall of the case body 81 issmaller than the width of the lower portion of the rear wall of the casebody 81, and the upper rear portion of the side wall of the case body 81is offset toward the center in the rightward or leftward direction.Thereby, a pair of rear recessed portions 85 which recede toward thecenter in the rightward or leftward direction are formed at right andleft sides of the upper rear portion of the case body 81. By providingthe rear recessed portions 85, the inner surface of the case body 81 canbe made closer to the rear portion of the outer surface of the uppersection 66, and the size of the case body 81 can be reduced to asmallest possible degree. In addition, as described above, the rider caneasily grip the case body 81 with the knee and increase the batterycapacity.

Schematically, each of the rear recessed portions 85 is surrounded by afirst offset side wall 86 which is substantially parallel to the sidewall and is located closer to the center in the rightward or leftwarddirection than the side wall, an offset rear wall 87 which issubstantially parallel to the rear wall and is located forward relativeto the rear wall, and a first offset upper wall 88 which issubstantially horizontal and connects the lower edge of the first offsetside wall 86 to the lower edge of the offset rear wall 87. The firstoffset upper wall 88 is connected to the side wall and rear wall of thecase body 81. The offset rear wall 87 is located forward relative to therear wall and rearward relative to the center of the entire case body 81in the forward or rearward direction.

The power wire 31 p extends rearward from the upper end portion of theright offset rear wall 87 along the outer surface of the first offsetside wall 86, and downward along the outer surface of the rear wall ofthe case body 81. The ground wire 31 n penetrates the left offset rearwall 87 and extends as in the power wire 31 p. Thus, the case body 81 isrequired to have a through-hole to guide the high-voltage electric wire31 from inside of the battery case 80 to outside. This through-hole isformed in the upper rear portion of the case body 81 and orientedrearward. This makes it possible to suitably prevent rain water or thelike from entering the battery case 80 through the through-hole.

The upper front portion of the side wall of the case body 81 is offsettoward the center in the rightward or leftward direction. Thereby, apair of front recessed portions 89 which recede toward the center in therightward or leftward direction are formed at right and left sides ofthe upper front portion of the case body 81. Schematically, each of thefront recessed portions 89 is surrounded by three side walls which are asecond offset side wall 90 which is substantially parallel to the sidewall and is located closer to the center in the rightward or leftwarddirection than the side wall, a second offset upper wall 91 which issubstantially horizontal and connects the side wall to the second offsetside wall 90, and an offset front wall 92 which vertically rises fromthe rear edge of the second offset side wall 90. The offset front wall92 is connected to the second offset side wall 90 and the side wall ofthe case body 81.

The opening 82 of the battery case 80 is defined by the upper edge ofthe front wall of the case body 81, the upper edges of the pair of firstoffset side walls 86, the upper edges of the pair of offset front walls92, the upper edges of the pair of side walls of the case body 81, theupper edges of the pair of offset rear walls 87, the upper edges of thepair of second offset side walls 90, and the upper edges of the rearwalls of the case body 81. The opening 82 basically has a rectangularshape when viewed from above, which surrounds the rectangular shape inwhich the inside electric components 30 are placed, from outside with alittle gap between the rectangular region and the opening 82. Since theopening 82 is thus formed, the inside electric components 30 can be seenand accessed through the opening 82. Furthermore, the opening 82 has ashape in which the intermediate portion of the rectangular shape in theforward or rearward direction protrudes rightward and leftward. Throughthis protruding portion, the terminal block 78 (see FIG. 3) for thehigh-voltage electric wire 31 can be seen, and maintenance of thehigh-voltage electric wire 31 can be carried out easily.

By comparison, the second offset upper wall 91 is lower than the upperedge of the wall defining the opening 82, and is located outward in therightward or leftward direction relative to the upper edge of the walldefining the opening 82. The second offset upper wall 91 covers thenon-mounting surface 61 d from above. This makes it difficult for therider or the maintenance operator to access a region outside of therectangular region, which is an advantage. In other words, the upperedge of the wall defining the opening 82 is higher than the uppersurface of the battery unit 60. This makes the upper edges of the wallsdefining the opening 82 higher than the inside electric components 30within the rectangular region, and the walls defining the opening 82 cancover the inside electric components 30 from forward, rearward,rightward and leftward. Therefore, in a state in which the opening 82 isopened, the inside electric components 30 can be favorably protectedfrom outside. In addition, the inside electric components 30 are placedwith a gap with the inner surface of the battery case 80. Therefore,even if water droplets are formed on the inner surface of the batterycase 80, it becomes possible to prevent a moisture from adhering to theinside electric components.

A battery monitoring unit 58 is mounted to the right side surface of thebattery case 80. As shown in FIG. 1, the vehicle control unit 59 ismounted to the left side surface of the battery case 80. Since the rightand left side surfaces of the battery case 80 are surrounded by the mainframes 12, the controllers 58, 59 can be favorably controlled. Inaddition, since many electronic components are arranged within thebattery case 80, the electric wires connected to the controllers 58, 59can be compactly laid out.

(Air Cooling of Battery Case)

FIG. 6 is a cross-sectional view of the battery case 80 of FIG. 4, whenviewed from rightward. As shown in FIG. 6, the inside electriccomponents 30, which are other than the DC/DC converter 45, are placedabove the battery unit 60. Therefore, heat radiated from the insideelectric components 30 is less likely to be transmitted to the batteryunit 60. This makes it possible to suitably suppress degradation of thebattery unit 60 by the heat. The inside electric components 30,including the DC/DC converter 45, are placed in the upper portion in theinterior of the battery case 80. Therefore, even if the rain water orthe like enters the battery case 80, the inside electric components 30is less likely to be immersed in water accumulated in the battery case80.

The battery case 80 includes an air inlet 101 provided at the frontportion of the case body 81 to introduce the air from outside into thebattery case 80, and an air outlet 102 provided at the rear portion ofthe case body 81 to discharge the air from inside of the battery case 80to outside. The air inlet 101 is placed to face the DC/DC converter 45.The air outlet 102 is disposed at the upper portion of the battery case80 in a position which is higher than the battery unit 60. The insideelectric components 30 are placed between the air inlet 101 and the airoutlet 102 in the forward or rearward direction.

The air discharge duct 22 is coupled to the air outlet 102. The innerspace of the battery case 80 is communicated with the inner space of theinverter case 19 (see FIG. 1) via the air outlet 102 and the airdischarge duct 22. The air outlet 102 is attached with the exhaust fan55. The indoor fan 56 is attached to the front portion of the innerbottom surface of the battery case 80. The indoor fan 56 is placedbetween the bottom wall of the battery case 80 and the bottom plateportion 67 of the battery frame 64.

With reference to FIG. 4, the front wall of the case body 81 includes aconverter cover section 103 covering the DC/DC converter 45, and theconverter cover section 103 has a pair of right and left taper portions103 a at right and left sides which are inclined rearward as they areoutward in the rightward or leftward direction.

The air inlet 101 penetrates the right taper portion 103 a, while theair-intake duct 21 is connected to an air inlet 101. The air-intake duct21 extends rearward such that it is inclined rightward from theair-intake port 21 a at an upstream end thereof and is connected to theair inlet 101. The air-intake duct 21 extends from the air-intake port21 a to the air inlet 101 in such a manner that it is firstly orienteddownward, then oriented substantially horizontally, and then orientedrearward and upward. Since the air-intake duct 21 has a portion which islower than the air-intake port 21 a and the air inlet 101, the rainwater or the like can be captured within the air-intake duct 21 even ifthe rain water or the like enters the air-intake duct 21 through theair-intake port 21 a. Thus, it becomes possible to suitably prevent therain water or the like from entering the battery case 80 through theair-intake duct 21. As described above, since the air-intake port 21 ais positioned forward relative to the front fork 6 (see FIG. 1), itbecomes possible to suitably prevent mud splashed by the front wheel 2from entering the air-intake duct 21.

With reference to FIG. 1, the converter cover section 103 is provided inan intermediate portion of the battery case 80 in the vertical directionsuch that the converter cover section 103 overlaps with the main frame12 and is close to the head pipe 11 in the forward or rearward directionwhen viewed from a side. Because of this, the air-intake port 21 a ispositioned forward relative to the front fork 6 with the air-intake duct21 reduced to a shortest possible length. Therefore, a passageresistance in the air-intake duct 21 can be reduced significantly, sothat the ram air can be smoothly sent to the interior of the batterycase 80.

FIG. 7 is a partial cross-sectional view of the battery case 80 of FIG.4. As shown in FIG. 7, the width of the DC/DC converter 45 is smallerthan the width of front portion of the upper section 66. The frontsurface of the upper section 66 constitutes an uncovered surface 61 ewhich is not covered with the DC/DC converter 45, in a portion which isoutward relative to the DC/DC converter 45 in the rightward or leftwarddirection. By comparison, as described above, the converter coversection 103 has the pair of taper portions 103 a, and the front surfaceof the DC/DC converter 45 is covered with a portion of the DC/DCconverter 45 which is sandwiched between the pair of taper portions 103a. The taper portions 103 a covers the uncovered surface 61 e and adistance between the uncovered surface 61 e and the inner surface oftaper portion 103 a increases toward the center in the rightward orleftward direction. Because of this, in the interior of the battery case80, there is formed an air space 104 of a substantially right triangleshape when viewed from above, which is surrounded by the taper portions103 a, the upper section 66 and the DC/DC converter 45, in a regionwhich is outward relative to the DC/DC converter 45 in the rightward orleftward direction.

The air inlet 101 opens in the air space 104 and faces the DC/DCconverter 45 with the air space 104. Because of this, the air cansmoothly flow into the battery case 80 after the air has flowed throughthe air-intake duct 21, and hence the interior of the battery case 80can be easily cooled by the ram air. In the interior of the battery case80, the air is blown to the DC/DC converter 45. Among the insideelectric components 30, especially, the DC/DC converter 45 generates agreat amount of heat during the operation. Since the air is blown to theDC/DC converter 45 in an initial stage of the air inflow to the batterycase 80, the DC/DC converter 45 can be suitably cooled by the air, andhence a temperature increase in the entire interior of the battery case80 can be suitably suppressed.

Turning back to FIG. 6, in the interior of the battery case 80, the airflows toward the air outlet 102. Since the inside electric components 30and the battery unit 60 are placed between the air inlet 101 and the airoutlet 102, heat radiated from the inside electric components 30 and thebattery unit 60 can be expelled to outside the battery case 80, by theair flow. Thus, it becomes possible to prevent a situation in which theheat radiated from the inside electric components 30 and the batteryunit 60 is accumulated in the interior of the battery case 80.Especially since the air outlet 102 is provided at the upper portion ofthe battery case 80, the air flows from the air inlet 101 toward the airoutlet 102 through the upper portion of the battery case 80. This makesit possible to suitably expel the heat transferred from the battery unit60 to an upper region, by convection, or the heat radiated from theinside electric components 30, to outside of the battery case 80.

During driving, the air sent to the battery case 80 increases in amount,which can rotate the exhaust fan 55 by itself irrespective of the fancontroller 57. According to the rotation of the exhaust fan 55, an airflow directed toward the exhaust fan 55 can be formed in the interior ofthe battery case 80. In light of this, during driving, the fancontroller 57 (see FIG. 2) does not electrically actuate the exhaust fan55. However, when the vehicle is in a stopped state or is driving at alow speed, a sufficient amount of air flow is not sent to the interiorof the battery case 80, and it may be difficult to rotate the exhaustfan 55 by itself. In light of this, when the vehicle speed becomes equalto or lower than a predetermined low speed, the fan controller 57electrically actuates the exhaust fan 55 to rotate it. The exhaust fan55 is electrically controlled in this way. During driving of thevehicle, the air flow is formed in the interior of the battery case 80and cools the interior of the battery case 80, without consuming theelectric power in the exhaust fan 55. On the other hand, under thesituation in which the air flow is not sent sufficiently, the interiorof the battery case 80 can be suitably cooled by using the exhaust fan55 which is electrically actuated.

The exhaust fan 55 may be controlled to be rotated in the same directionas the direction in which the exhaust fan 55 rotates itself, to form theair flow from the air inlet 101 toward the air outlet 102, or in adirection opposite to the direction in which the exhaust fan 55 rotatesitself, to form the air flow from the air outlet 102 toward the airinlet 101.

The indoor fan 56 may be controlled to operate along with the exhaustfan 55 during, for example, a charging work. At this time, the air blownfrom the indoor fan 56 flows toward the exhaust fan 55. The indoor fan56 is provided at the front portion of the inner bottom surface of thebattery case 80, while the exhaust fan 55 is provided at the upper rearportion of the battery case 80. Because of this, the air flows from theindoor fan 56 toward the exhaust fan 55 through the battery unit 60 suchthat the air flow is directed upward and rearward. Therefore, the heatradiated from the battery unit 60 during the charging can be expelled tooutside the battery case 80. The indoor fan 56 may be controlled tooperate during driving and a temporarily stopped state.

After flowing through the air outlet 102, the air is guided to theinterior of the inverter case 19 (see FIG. 1) through the air dischargeduct 22. Among the electric components mounted in the electricmotorcycle 1, especially, the inverter 20 (see FIG. 1) generates a greatamount of heat during its operation. Therefore, the inverter 20 can becooled by the air discharged from the battery case 80. Since the airdischarge duct 22 for discharging the air from the battery case 80serves as a duct for supplying cooling air to the interior of theinverter case 19, the configuration of the entire device for cooling theelectric components by the air can be simplified.

It should be noted that air discharge duct 22 may be omitted. Even ifthe air discharge duct 22 is omitted, it becomes possible to suitablyprevent the rain water or the like from entering the battery case 80through the air outlet 102, because the air outlet 102 is provided atthe upper portion of the battery case 80. In the above stated example,only the air outlet 102 is provided at the upper portion of the batterycase 80. However, so long as at least one of the air inlet 101 and theair outlet 102 is provided at the upper portion of the battery case 80,the inside electric components 30 placed on the battery unit 60 can besuitably cooled by the air flowing from the air inlet 101 toward the airoutlet 102.

(Mounting of Battery Case and Battery Assembly)

Next, assembling of the battery case 80 and mounting of the battery case80 and the battery assembly 79 will be described. As shown in FIG. 5,the battery case 80 includes a first case member 111 and a second casemember 112, which are joined together such that they are horizontallyseparable from each other. These two case members 111, 112 aremanufactured by molding using a synthetic resin which is a materialhaving an electric insulativity. These two case members 111, 112 aremanufactured by a material having a smaller specific weight and a lowerstiffness than the material of the battery frame 64 and the material ofthe vehicle body frame 4.

By joining these two case members 111, 112 together, the case body 81having the opening 82 is formed. In the present embodiment, the firstcase member 111 and the second case member 112 are separable from eachother in the forward or rearward direction.

The first case member 111 includes a first body section 113 constitutingthe front portion of the case body 81 and a first flange section 114provided at the rear end of the first body section 113. The second casemember 112 includes a second body section 115 constituting the rearportion of the case body 81 and a second flange section 116 provided atthe front end of the second body section 115. The first flange section114 is engageable with the second flange section 116 such that the firstflange section 114 is directly or indirectly joined to the second flangesection 116 without a clearance in a thickness direction. The outersurface of the first flange section 114 is provided with a plurality offirst case joining sections 117 into which bolts 133 are inserted,respectively. The outer surface of the second flange section 116 isprovided with a plurality of second case joining sections 118.

The first body section 113 has, in a state in which the battery case 80is incorporated into the electric motorcycle 1, a bottom wall, andfront, left and right walls extending upward from the bottom wall suchthat they are bent, and opens rearward and upward. The first flangesection is provided adjacently to the rear end of the first bodysection, and thus has a substantially-U shape when viewed from rearward.The second body section 115 has, in a state in which the battery case 80is incorporated into the electric motorcycle 1, a bottom wall, rear,left and right walls extending upward from the bottom wall such thatthey are bent and opens forward and upward. The second flange section116 is provided adjacently to the front end of the second body section115, and thus has a substantially-U shape when viewed from rearward.

The flange sections 114, 116 protrude outward of the case (except forforward or rearward because each of the flange sections 114, 116 is notprovided at the front wall and the rear wall) farther than thecorresponding adjacent portions of the body sections 113, 115. The term“outward of the case” means outward of the battery case 80 in thethickness of the battery case 80. “outward of the case” is leftward fromthe perspective of the left wall of the first body section 113 and isdownward from the perspective of the bottom wall of the first bodysection 113. Inward of the case is opposite to “outward of the case”.“Inward of the case” is rightward from the perspective of the left wallof the first body section 113 and is upward from the perspective of thebottom wall of the first body section 113. The thickness of the flangesections 114, 116 is greater than the thickness of the adjacentportions.

Now, the steps of assembling the battery case 80 and the steps ofjoining the battery case 80 and the battery assembly 79 to each otherwill be described in brief. The directions described below are from theperspective of the rider in a state in which the assembling is finishedand the battery case 80 and the battery assembly 79 are mounted to thevehicle body frame 4.

(1) Initially, the second case member 112 is moved in the forward orrearward direction relative to the battery assembly 79, and the rearportion of the battery assembly 79 is stored into the second bodysection 115 through a U-shaped open space defined by the second flangesection 116. (2) Then, the battery assembly 79 is joined to the secondcase member 112. At this time, the front portion of the battery assembly79 protrudes forward farther than the second flange section 116. (3)Then, the first case member 111 is moved in the forward or rearwarddirection relative to the battery assembly 79, and the front portion ofthe battery assembly 79 is stored into the first body section 113through a U-shaped open space defined by the first flange section 114.In a final stage of this storage, the first flange section 114 and thesecond flange section 116 are engaged with each other and the first casejoining sections 117 and the second case joining sections 118 contacteach other. (4) Then, the bolts are inserted into the first case joiningsections 117 and the second case joining sections 118, respectively.Thereby, the first case member 111 and the second case member 112 arefastened to each other, thereby constituting the case body 81. (5) Then,the upper lid 83 is detachably joined to the case body 81 such that theupper lid 83 covers the opening 82 of the case body 81. Thus, thebattery case 80 containing the battery assembly 79 is finished.

In description below, in some cases, a relative movement direction(e.g., forward) of the second case member 112 in the case where thebattery assembly 79 is stored into the second body section 115, and arelative movement direction (e.g., rearward) of the first case member111 in the case where the battery assembly 79 is stored into the firstbody section 113 will be referred to as “insertion direction.” Since thefront surface of each of the first case joining sections 117 and therear surface of the corresponding second case joining section 118 are incontact with each other when two case members 111, 112 are joinedtogether, the front surface of each of the first case joining sections117 and the rear surface of the corresponding second case joiningsections will be hereinafter sometimes collectively referred to as“joint surfaces”. In a state in which the two case members 111, 112 arejoined together, the two flange sections 114, 116 which are engaged witheach other constitute the separable portions of the case body 81. In thepresent embodiment, as will be described later, since the flangesections 114, 116 are fitted together, they do not form a separation“line” in a strict sense.

The flange section (i.e., first flange section 114) formed in the casemember (i.e., first case member 111) which is forward relative to theseparable portions, covers the other case member (i.e., second casemember 112), from outward of the case. In the separable portions, theflange sections 114, 116 directly or indirectly overlap with each otherin the thickness direction. In the present embodiment, as will bedescribed later, a recessed portion which opens rearward is formed inthe first flange section 114 placed at a forward side, and a convexportion fitted to the recessed portion in engagement is formed in thesecond flange section 116 placed at a rearward side, thereby forming theabove stated overlapping portions.

Since the case body 81 is dividable in the forward or rearwarddirection, the joint surfaces extend substantially in the rightward orleftward direction and substantially in the vertical direction, and theparting line extends in the rightward or leftward direction above thebottom wall of the case body 81 and in the vertical direction above thepair of right and left side walls. In the present embodiment, theparting line extends in the rightward or leftward direction above thecenter portion of the bottom wall in the forward or rearward direction.As described above, the rear upper portion of the battery assembly 79 isoffset rearward relative to the rear lower portion of the batteryassembly 79, while the front upper portion of the battery assembly 79 isoffset rearward relative to the front lower portion of the batteryassembly 79. When the second case member 112 at a rear side, of the twocase members 111, 112, is firstly mounted to the battery assembly 79, aprotruding portion of the upper portion of the battery assembly 79,which protrudes from the second case member 112, after the step (2), canbe reduced. Therefore, the battery assembly 79 can be favorablyprotected when the step (2) and the step (3) are performed.

Hereinafter, the structure associated with the steps (1) to (4) will bedescribed.

(Flange Section)

Initially, the flange sections 114, 116 associated with the step (3)will be described. FIGS. 8 and 9 are partial cross-sectional views ofthe battery case 80 of FIG. 1, when viewed from above. As shown in FIGS.8 and 9, the case body 81 is configured such that the first flangesection 114 is oriented rearward and the second flange section 116 isoriented forward. The first flange section 114 protrudes outward of thecase from the rear end portion of the first body section 113 and then isbent rearward, thus having a substantially-L-shaped cross-section. Inother words, the first flange section 114 includes a first outwardprotruding portion 121 which protrudes outward of the case from the rearend portion of the first body section 113, and a rearward protrudingportion 122 which protrudes rearward from the tip end of the firstoutward protruding portion 121.

In other words, the first flange section 111 has a cover portionextending from the first body section 113 in a direction different fromforward in a driving direction and beyond the parting line (or front endof the second flange section 116). Preferably, the cover portion 122extends rearward. However, the cover portion 122 may extend in anydirection except for forward.

The first case member 111 has an extending portion 123 extendingrearward from the rear edge of the first body section 113. The extendingportion 123 is parallel to the rearward protruding portion 122 of thefirst flange section 114. Although in FIGS. 8 and 9, only thecross-section is shown, the extending portion 123 is provided with nodiscontinuity at the rear end portion of the first body section 113 suchthat it has a U-shape when viewed from rearward, as in the first flangesection 114. Thereby, there is formed an engagement groove 124 at therear end of the first case member 111, which is surrounded by the firstflange section 114 and the extending portion 123. The engagement groove124 opens rearward and has a U-shape when viewed from rearward.

The second flange section 116 protrudes outward of the case from thefront end portion of the second body section 115 and then is bentforward. The second flange section 116 includes a second outwardprotruding portion 125 which protrudes outward of the case from thefront end portion of the second body section 115, and a forwardprotruding portion 126 which protrudes forward from the tip end of thesecond outward protruding portion 125. The tip end of the forwardprotruding portion 126 is an engagement protrusion 127 fitted to theengagement groove 124. The forward protruding portion 126 has athickened portion 128 which is provided rearward relative to theengagement protrusion 127 and has a greater thickness than theengagement protrusion 127 and the second body section 115. The outersurface of the thickened portion 128 is coplanar with the outer surfaceof the engagement protrusion 127. Because of this, the inner surface ofthe thickened portion 128 is located inward of the case relative to theinner surface of the engagement protrusion 127.

In the step (3), when the engagement protrusion 127 is received in theengagement groove 124, at least a portion of the thickened portion 128overlaps with the rearward protruding portion 122 of the first flangesection 113, in the thickness direction of the case. The rearwardprotruding portion 122 is located outward of the case relative to thesecond flange section 115. Therefore, a clearance 129 formed between thefirst flange section 113 and the second flange section 114 has alabyrinth shape. Specifically, the clearance 129 includes a clearance129 a extending in the forward or rearward direction, between the innersurface of the rearward protruding portion 122 and the outer surface ofthe forward protruding portion 126, a clearance 129 b formed forwardrelative to the engagement protrusion 127, and a L-shaped clearance 129c formed between the inner surface of the forward protruding portion 126and the extending portion 123. The front end of the clearance 129 aopens to outside of the battery case 80, while the inner end of theclearance 129 c opens to inside of the battery case 80. The clearance129 is turned back at a right angle three times in a range from thefront end of the clearance 129 a to the end of the clearance 129 c whichis inward of the case.

Since the first flange section 113 is oriented rearward, the front endof the clearance 129 a is also oriented rearward. Therefore, even whenthe two case members 111, 112 are separably joined together to form thecase body 81, it becomes possible to suitably prevent the rain water orthe like from entering the clearance 129 formed in the location at whichthe two case members 111, 112 are separable from each other. Even if therain water or the like enters the clearance 129, it becomes possible tosuitably prevent the rain water or the like from entering the batterycase 80, because the clearance 129 has the labyrinth shape.

A seal 130 which is an elastic body made of rubber or the like may beprovided in advance in the clearance 129 b. The seal 130 may be crushedby the engagement protrusion 127 and elastically deformed by a forwardpressing force, thereby sealing the clearance 129 c from the clearance129 a. The seal 130 is elastically deformed in the forward or rearwarddirection, i.e., direction in which the bolts 133 are inserted. Bymaintaining the elastically deformed state by the fastening member inthis way, the clearance is not formed between the case members 111, 112.In this case, even when the rain water or the like enters the clearance129 a, it becomes possible to prevent the rain water or the like fromentering the interior of the battery case 80.

The engaged state between the first flange section 114 and the secondflange section 116 refers to a state in which a portion of the firstflange section 114 and a portion of the second flange section 116, whichportions vertically overlap with each other, exist in the vicinity ofthe parting line formed above the bottom surface, in the case body 81 inthe joined state, for example, a state in which the convex portion isfitted into the recessed portion. Since the thickness of the case in thevicinity of the parting line is greater than the thickness of theremaining portion in the case body 81 in the joined state, the stiffnessof the case for bearing the battery unit 80 (or the battery assembly 79)from below can be improved. In other words, the flange sections 114, 116are preferably formed with contact surfaces by which the flange sections114, 116 are vertically in contact with each other, in a positiondifferent from the parting line.

As described above, the two flange sections 114, 116 protrude outward ofthe case, from the first body section 113 and the second body section115, respectively. In addition, the two flange sections 114, 116 areengaged with each other so as to overlap with each other in thethickness direction of case. Therefore, when the battery case 80 is seenin a macroscopic manner, the two flange sections 114, 116 serve as ribswith a great thickness extending with no discontinuity above the leftside wall, the bottom wall and the right side wall, in the centerportion of the case body 81 in the forward or rearward direction. Thiscan improve the stiffness of the case body 81. Especially, in thepresent embodiment, since the first and second case members 111, 112 areseparable from each other in the forward or rearward direction, the twoflange sections 114, 116 serving as the ribs extend above the bottomsurface. This allows the battery case 80 made of a synthetic resin tostably bear the battery assembly 79 with a heavy weight. The two flangesections 114, 116 constitute the parting line. Since the parting linehas a high strength, the stiffness of the case body 81 can be improvedeven when the case body 81 is formed by joining the two case members111, 112 together such that they are separable from each other.

In the case body 81 which is dividable, the first flange section 114located outward of the case may be oriented in any direction other thanforward, to suitably prevent entry of the rain water or the like.

To merely improve the stiffness, it is sufficient that the flangesections 114, 116 extend above the bottom wall. In this case, the casebody 81 may be dividable horizontally, including a component in therightward or leftward direction, or a component in the forward orrearward direction and the component in the rightward or leftwarddirection. In a case where the case body 81 is dividable in the forwardor rearward direction, entry of the rain water or the like can besuitably prevented and the stiffness can be improved.

(Case Joining Section)

Next, the case joining sections 117, 118 associated with the step (3)and the step (4) will be described. As shown in FIG. 8, the first casejoining section 117 is provided on the outer surface of the forwardprotruding portion 126 of the first flange section 114. The first casejoining section 117 has a bottomed cylinder shape which opens at itsfront end and is closed at its rear end. The axis of the first casejoining section 117 is oriented in the forward or rearward direction ina location outward of the case relative to the first body section 113.The first case joining section 117 contains a metal-made nut 131. Inthis way, the first case joining section 117 is a hexagon cap nut havingthe outer surface made of a synthetic resin and a threaded inner surfacemade of metal. The nut 131 may be manufactured by insert-molding, orpressed-in after the first case member 111 is molded. The second casejoining section 118 is provided on the outer surface of the thickenedportion 128 of the second flange section 116. The second case joiningsection 118 has a cylindrical shape which opens at both ends. The axisof the second case joining section 118 is oriented in the forward orrearward direction in a location outward of the case relative to thesecond body section 115. The second case joining section 118 has anaxial hole 132 which opens in the forward or rearward direction.

In the step (3), concurrently with the engagement between the two flangesections 114, 116, the front surface of the first case joining section117 contacts the rear surface of the second case joining section 118,and the axial hole 132 is communicated with the nut 131. In the step(4), the bolt 133 is inserted into the axial hole 132 from behind thesecond case joining section 118 and threadingly engaged with the nut131. This allows the two case members 111, 112 to be firmly joinedtogether.

As described above, the two case joining sections 117, 118 are providedon the outer surface of the battery case 80. In other words, the batterycase 80 is not provided with a through-hole for joining the two casemembers 111, 112 together. This makes it possible to prevent the rainwater or the like from entering the battery case 80. Furthermore, theaxial hole 132 opens rearward. This makes it possible to suitablyprevent a situation in which the head portion of the bolt 133 or theaxial hole 132 is clogged with mud splashed by the wheels 2, 3 (see FIG.1), and disassembling work of the battery case 80 becomes messy. Thefirst case joining section 117 constitutes a hexagon cap nut closed atits front end. Therefore, the nut 131 is not clogged with mud.

The case joining sections 117, 118 do not have a through-hole in thethickness direction of the battery case 80. In the battery case 80provided with the case joining sections 117, 118, a hole forcommunicating the interior and exterior of the battery case 80 with eachother is not formed. In the present embodiment, as described above, thenut 131 having the axis extending in the forward or rearward directionoutside the case is buried during the molding of one of the case members(e.g., first case member 111). The nut and the through-hole areconfigured so that the center axis of the nut and the center axis of thethrough-hole are aligned with each other when the case members areengaged with each other. By engaging the fastening member (bolt 133)inserted into the through-hole 132, with the nut 131, the pair of casemembers 111, 112 are fastened to each other in the forward or rearwarddirection.

When the hole does not penetrate the nut 131, the nut having the axis inthe thickness direction of the battery case 80 may be buried. In theabove configuration which is different from this, since the pair of casemembers are separable from each other in the forward or rearwarddirection, and the hole of the nut 131 extends in the forward orrearward direction, it becomes possible to prevent the interior of thebattery case 80 from being communicated with the exterior of the batterycase 80. Alternatively, the case joining sections 117, 118 may have thethrough-holes extending in the forward or rearward direction,respectively, the center axes of these through-holes may be aligned witheach other when the case members 111, 112 are engaged with each other,and the pair of case members 111, 112 may be fastened to each other inthe forward or rearward direction by the fastening member inserted intothe through-holes.

(Positioning Section)

Next, positioning sections 140, 145 associated with the step (1) and thestep (3) will be described. As shown in FIG. 6, the second case member112 has a positioning portion 141 protruding inward of the case, fromthe inner wall in the insertion direction in the step (1). In thepresent embodiment, the insertion direction is the forward or rearwarddirection, and the second case member 112 is movable forward relative tothe battery assembly 79 in the step (1). Because of this, thepositioning portion 141 protrudes forward in a substantially horizontaldirection from the rear wall of the second body section 115. Bycomparison, the intermediate plate portion 71 of the battery frame 64has in its rear surface an open slit 142. The positioning portion 141and the slit 142 constitute the positioning section 140 for positioningthe battery assembly 79 with respect to the second case member 112.

The first case member 111 has a positioning portion 146 protrudinginward of the case, from the inner wall in the insertion direction inthe step (3). In the present embodiment, the insertion direction is theforward or rearward direction, and the first case member 111 is movablerearward relative to the battery assembly 79 in the step (3). Because ofthis, the positioning portion 146 protrudes rearward in a substantiallyhorizontal direction from the front wall of the first body section 113.By comparison, the lower front cover portion 69 of the battery frame 64has in its front surface an open slit 147. The positioning portion 146and the slit 147 constitute the positioning section 145 for positioningthe battery assembly 79 with respect to the first case member 111.

The positioning portions 141, 146 are, for example, metal plates, andare provided during molding of the corresponding case members 111, 112,by insert-molding. FIG. 6 is a side cross-sectional view, and thereforeonly one positioning section 140 is shown. However, the plurality ofpositioning sections 140 may be provided to be spaced apart from eachother in the rightward or leftward direction (direction orthogonal tothe drawing sheet of FIG. 6). The same applies to the positioningsections 145.

In the step (1), the second case member 112 is moved in the insertiondirection relative to the battery assembly 79. When the rear portion ofthe battery assembly 79 becomes close to the inner rear surface of thesecond case member 112, the positioning portion 141 is inserted into theslit 142. This allows the battery assembly 79 to be positioned withrespect to the second case member 112. Therefore, in the step (2), thesecond case member 112 can be easily fastened to the battery assembly79. In the step (3), the same occurs as follows. The first case member111 is moved in the insertion direction relative to the battery assembly79. When the front portion of the battery assembly 79 becomes close tothe inner front surface of the first case member 111, the positioningportion 146 is inserted into the slit 147.

In a state in which the positioning portions 141, 146 are inserted intothe corresponding slits 142, 147, respectively, it is possible tosuitably inhibit the battery assembly 79 from being moved relatively inthe vertical direction and in the rightward or leftward direction. Thetwo positioning sections 140, 145 can cooperate to inhibit the batteryassembly 79 from being moved in the forward or rearward direction withrespect to the two case members 111, 112. This makes it possible toinhibit the battery assembly 79 from being displaced with respect to thebattery case 80 in the interior of the battery case 80. As a result, aweight balance of the vehicle can be stabilized during driving.

The positioning sections 140, 145 having the above configuration areplaced in the inner space of the battery case 80. In a state in whichthe assembling of the battery case 80 is completed, the positioningsections 140, 145 cannot be seen from outside. That is, the battery case80 is not provided with the through-hole for positioning the batteryassembly 79 with respect to the two case members 111, 112. This makes itpossible to suitably prevent the rain water or the like from enteringthe battery case 80 while allowing the battery assembly 79 to bepositioned with respect to the case members 111, 112.

(Battery Fastening Section)

Next, a battery fastening section 150 associated with the step (2) willbe described. As shown in FIG. 6, the intermediate plate portion 71 ofthe battery frame 64 has a pair of right and left threaded holes 151which open outward in the rightward or leftward direction (In FIG. 6,only the right threaded hole 151 is shown).

As shown in FIG. 9, the second case member 112 includes a pair of rightand left brackets 152 (in FIG. 9, only the right bracket 152 is shown)for fastening the second case member 112 to the battery assembly 79. Thebrackets 152 are manufactured by bending the metal plates and buriedinto the second case member 112 by insert-molding during the molding ofthe second case member 112. Each of the brackets 152 includes an inwardprotruding portion 153 protruding inward of the case from the thickenedportion 128 of the second flange section 116, and a mounting portion 154which protrudes forward from the tip end of the inward protrudingportion 153 such that it is bent. The threaded holes 151 and thebrackets 152 constitute the battery fastening section 150 for fasteningthe battery assembly 79 to the battery case 80.

As described above, in the step (1), in a state in which the batteryassembly 79 is positioned with respect to the second case member 112 byusing the positioning section 140 (see FIG. 6), the inner surface ofeach of the mounting portions 154 contacts the side surface of theintermediate plate portion 71. A through-hole 155 formed in the mountingportion 154 is connected to the threaded hole 151 which opens in theside surface of the intermediate plate portion 71. In the step (2), abolt 156 is inserted into the through-hole 155 from outside in therightward or leftward direction and threadingly engaged with thethreaded hole 151. This allows the second case member 112 to be firmlyfastened to the battery assembly 79 via the brackets 152. Since themounting portion 154 protrudes forward farther than the front end of thesecond flange section 116, fastening of the bolt 156 can be carried outeasily.

As described above, the brackets 152 are provided on the second flangesection 116 which contributes to improvement of the strength of thebattery case 80. Since the battery assembly 79 is coupled to the secondflange section 116 via the brackets 152, the battery case 80 can stablysupport the battery assembly 79. In addition, it becomes possible toinhibit the battery assembly 79 from being displaced with respect to thebattery case 80 in the interior of the battery case 80. As should beunderstood from this, along with the positioning sections 140, 145 thebattery fastening section 150 also serve as the positioning section forinhibiting the battery assembly 79 from being displaced. Especially, inthe present embodiment, since the brackets 152 are buried into thethickened portion 128 of the second flange section 116, the batteryassembly 79 can be stably supported.

The battery fastening section 150 is placed in the inner space of thebattery case 80. In a state in which the assembling of the battery case80 is completed, the battery fastening section 150 cannot be seen fromoutside. That is, the battery case 80 is not provided with thethrough-hole for fastening the battery assembly 79 to the battery case80. This makes it possible to suitably prevent the rain water or thelike from entering the battery case 80 while allowing the batteryassembly 79 to be firmly fastened to the battery case.

(Mounting of Battery Case to Vehicle Body Frame)

Hereinafter, a procedure for mounting the battery case 80 to the vehiclebody frame 4 (especially down frames 13) will be described. As shown inFIG. 6, there are provided buffer members 161 between the bottom plateportion 67 of the battery frame 64 and the inner bottom surface of thecase body 81. The buffer members 161 are made of, for example, rubber.The battery frame 64 has a higher elasticity than the battery case 80,of course. The buffer members 161 may be fastened to the battery case80, or to the battery frame 64. In either case, in a state in which thebattery assembly 79 is stored in the battery case 80, the buffer members161 are in contact with the battery frame 64 and the battery case 80. Inthe present embodiment, eight buffer members 161 in total are placed inright and left rows, and four buffer members 161 on each row arearranged to be spaced apart in the forward or rearward direction. In theside cross-sectional view of FIG. 6, only the four buffer members 161(one row) are shown.

FIG. 10 is a bottom view of the down frames 13 and the battery case 80of FIG. 1. The down frames 13 include a front horizontal frame member 13c coupled to the lower end portions of the pair of right and leftvertical frame members 13 a and a rear horizontal frame member 13 dcoupled to the pivot frames 14, and the horizontal frame members 13 c,13 d extend in the rightward or leftward direction. The front endportions of the pair of right and left lower frame members 13 b arewelded to the front horizontal frame member 13 c, while the rear endportions of the pair of right and left lower frame members 13 b arewelded to the rear horizontal frame member 13 d.

The distance between the pair of lower frame members 13 b in therightward or leftward direction is smaller than the distance between thepair of main frames 12 in the rightward or leftward direction. Becauseof this, by inserting the battery case 80 into a space between the pairof main frames 12 from above the main frames 12, the bottom portion ofthe battery case 80 is suitably placed on the pair of lower framemembers 13 b.

Regarding the distance between the lower frame members 13 b in therightward or leftward direction, the distance between the rear endportions is smaller than the distance between the front end portions.This can make the layout of components in the vicinity of the lower endportions of the pivot frames 14 compact in the rightward or leftwarddirection. In the vicinity of the lower end portions of the pivot frames14, a shift pedal (not shown) for a shifting operation, a brake pedal(not shown) for a braking operation, and the like are placed. Because ofthe compact layout of these components, the rider can perform theshifting operation and the braking operation without a need to stretchthe rider's feet to the right and to the left.

To implement such a layout, the pair of lower frame members 13 b extendrearward from the front horizontal frame member 13 c such that theyextend in parallel, are curved toward the center in the rightward orleftward direction so as to reduce a distance between them, and thenextend rearward in parallel. With reference to FIG. 1, each of the lowerframe members 13 b is bent to protrude downward in the vicinity of theflange sections 114, 116 extending above the bottom wall of the batterycase 80 so that the bottom portion of the battery case 80 is mountableon the lower frame member 13 b and interference between the lower framemember 13 b and the flange sections 114, 116 is avoided. With referenceto FIG. 9, the pair of lower frame members 13 b are connected to eachother via two connecting frames 13 e, 13 f extending in the rightward orleftward direction. These two connecting frames 13 e, 13 f are placedsuch that the flange sections 114, 116 are sandwiched between them inthe forward or rearward direction. This allows the lower frame members13 b bent in the vertical direction and in the rightward or leftwarddirection to have a high stiffness, and hence to bear the battery case80 with a heavy weight.

The distance between the rear end portions of the lower frame members 13b is smaller than the distance between the front end portions of thelower frame members 13 b, while the width of the bottom portion of thebattery case 80 from the front end portion to the rear end portion issubstantially constant in the forward or rearward direction. So, a stay13 g which is elongated in the rightward or leftward direction is joinedto the rear end portions of the pair of lower frame members 13 b. Thestay 13 g is externally fitted to the right and left lower frame members13 b. In this state, the stay 13 g is welded to the right and left lowerframe members 13 b and to the rear connecting frame 13 f. In this way,the stay 13 g is integrated with the down frames 13. The stay 13 ghaving such a structure can stably support the right and left ends ofthe rear bottom portion of the battery case 80, even though the distancebetween the rear end portions of the lower frame members 13 b is small.

The battery case 80 is supported on the upper surfaces of the lowerframe members 13 b and the upper surface of the stay 13 g in the mannerdescribed above, and then fastened to the down frames 13. To fasten thebattery case 80 to the down frames 13, a pair of right and left brackets162 are welded to the front end portions of the lower frame members 13b. Each of the brackets 162 includes a cylindrical portion 163externally fitted to the lower frame member 13 b and a mounting portion164 having a butterfly shape when viewed from above and protruding inthe rightward or leftward direction from the cylindrical portion 163.The mounting portion 164 has a bolt insertion hole 165 penetratingtherethrough, into which a bolt 168 (see FIG. 11) is inserted.

FIG. 11 is a partial cross-sectional view of the down frames 13 and thebattery case 80 of FIG. 10, when viewed from forward. As shown in FIG.11, the bottom wall of the battery case 80 is provided withreinforcement portions 166 in portions which the brackets 162 contact,respectively. The reinforcement portions 166 are, for example, metalplates. Since the brackets 162 are provided at the front end portions ofthe lower frame members 13 b, respectively, the reinforcement portions166 are provided on the first case member 111 at a front side byinsert-molding during the molding of the first case member 111. Thereinforcement portions 166 have a higher vertical strength, for example,strength to a compressive load and a tensile load, than the remainingportion of the battery case 80 made of a synthetic resin. Threaded holes167 open in the lower surfaces of the reinforcement portions 166,respectively. On the other hand, the lower surface of the battery case80 is not provided with through-holes including a threaded hole.

When the battery case 80 is inserted in a space between the main frames12, the lower surfaces of the reinforcement portions 166 are broughtinto surface contact with the upper surfaces of the brackets 162,respectively. At this time, the bolt insertion holes 165 of the bracketsare aligned with the threaded holes 167 of the reinforcement portions166, respectively. Then, the bolts 168 are inserted into the boltinsertion holes 165, respectively, from below, and threadingly engagedwith the threaded holes 167, respectively. This allows the battery case80 to be fastened to the down frames 13 and hence firmly fastened to thevehicle body frame 4. Between each of the down frames 13 and thecorresponding reinforcement portion 166, a spacer 169 made of metal issuitably provided. By providing the spacer 169, the reinforcementportion 166 can be supported properly on the down frame 13 via thespacer 169.

When the battery case 80 is mounted to the down frames 13 as describedabove, the battery assembly 79 is supported on the upper surfaces of thedown frames 13, and the battery case 80 is located between the lowersurface of the battery assembly 79 and the upper surfaces of the downframes 13. Therefore, the down frames 13 bear the weight of the batteryassembly 79 from below. This can reduce a need for increasing astiffness of the battery case 80 to bear the load. As a result, thematerial of the battery case 80 can be selected more flexibly. Forexample, the battery case 80 which can attain a reduced weight andinsulativity can be manufactured easily. In the present embodiment, adedicated component (i.e., battery frame 64) for fastening the batterymodules 61 is provided, and a component (i.e., battery case 80) forstoring the battery modules is separate from the component for fasteningthe battery modules 61. As a result, the material of the battery case 80can be selected more flexibly.

The weight load of the battery assembly 79 is exerted on the down frames13 via the buffer members 161 which are in contact with the batteryframe 64 and the bottom portion of the battery case 80 which is incontact with the buffer members 161. In the bottom portion of thebattery case 80, the weight load of the battery assembly 79 is stronglyexerted on a portion between a portion which is in contact with the downframes 13 and a portion which is in contact with the buffer members 161.In the present embodiment, in a portion of the bottom portion of thebattery case 80, which is in contact with the down frames 133, thereinforcement portions 166 are provided. Since the portion on which thestrong load is exerted is especially reinforced, the strength of theentire battery case 80 can be improved without a need to reinforce theentire battery case 80.

The battery case 80 is fastened to the down frames 134 via thereinforcement portions 166. Since the battery case 80 is fastened to thedown frames 134 by utilizing the portions with a high strength, it canbe firmly fastened to the vehicle body frame 4. In addition, the lengthof the shaft portion of the bolt 168 is smaller than a sum of the axiallength of the bolt insertion hole 165 and the axial length of thethreaded hole 167. Therefore, the bolt 168 does not penetrate thereinforcement portion 166 to the interior of the battery case 80. Inother words, the bottom portion of the battery case 80 is not providedwith a through-hole for joining the battery case 80 to the down frames13. This makes it possible to suitably prevent the rain water or thelike from entering the battery case 80 while allowing the battery case80 to be firmly fastened to the vehicle body frame 4.

In addition, the elastic buffer members 161 are placed between thebattery assembly 79 and the battery case 80. For example, duringdriving, the elastic buffer members 161 are able to absorb the impactexerted on the battery unit 60 by the wheels 2, 3 (see FIG. 1). Thismakes it possible to mitigate the impact exerted on the battery case andinhibit a vibration of the battery assembly 79.

With reference to FIGS. 10 and 11, the eight elastic buffer members 161in total are placed so as to overlap with the down frames 13 when viewedfrom above. The four buffer members 161 on a left row are placed so asto substantially overlap with the left lower frame member 13 b, whilethe four buffer members 161 on a right row are placed so as tosubstantially overlap with the right lower frame member 13 b. Among thebuffer members 161, the buffer members 161 located at a rearmost side donot overlap with the lower frame members 13 b but overlap with the stay13 g integrated with the down frames 13 when viewed from above.

If the buffer members 161 are distant from the down frames 13 whenviewed from above, the weight load of the battery assembly 79 which isexerted on the buffer members 161, is received by the down frames 13which are distant when viewed from above. This causes a shear force tobe exerted on a portion of the battery case 80 which is between thebuffer members 161 and the down frames 13. In the present embodiment,the weight load of the battery assembly 79 which is exerted on thebuffer members 161, is linearly exerted on the down frames 13 fromabove. Thereby, the load exerted on the portion of the battery case 80which is between the buffer members 161 and the down frames 13 isprimarily a compressive load, and the shear force exerted on the portionof the battery case 80 is mitigated. The synthetic resin has relativelyhigh endurance to the compressive load and relatively low endurance tothe shear load. In the present embodiment, since the shear force exertedon the battery case 80 is mitigated, the weight of the battery case 80can be reduced, and the life of the battery case 80 can be extended, bymolding the battery case 80 using the synthetic resin. As should beunderstood, the stay 13 g not only stably supports the rear bottomportion of the battery case 80 but also contributes to a reduction ofthe shear force exerted on the battery case 80. What is needed toachieve this advantage is to place the buffer members 161 such that theyoverlap with the down frames 13 when viewed from above. Therefore,instead of arranging the plurality of small buffer members 161 such thatthey are apart from each other in the forward or rearward direction, thebuffer members 161 which are elongated in the forward or rearwarddirection may be placed.

FIG. 12 is a partial cross-sectional view of the down frame 13 and thebattery case 80 according to a modified example, when viewed fromforward. FIG. 13 is a partial cross-sectional view of the down frame andthe battery case according to another modified example, when viewed fromforward. In the modified example of FIG. 12, a bracket 262 includes afirst bracket member at a right side and a second bracket member at aleft side which are joined together. The first bracket member and thesecond bracket member are separable from each other in the rightward orleftward direction. The bracket 262 is formed by fastening these bracketmembers to each other by a bolt 270. The first bracket member includes asemi-cylindrical portion 263A covering the right portion of the downframe 13, and a mounting portion 264A protruding to the right from theupper end portion of the semi-cylindrical portion 263A. The secondbracket member includes a semi-cylindrical portion 264B covering theleft portion of the down frame 13, and a mounting portion 264Bprotruding to the left from the left upper end portion of thesemi-cylindrical portion 263B. Bolt insertion holes 265A, 265B penetratethe mounting portions 264A, 264B, respectively. The two semi-cylindricalportions 263A, 263B are joined at their lower end portions to each otherin the rightward or leftward direction. A bolt 270 is inserted into thelower end portions of the two semi-cylindrical portions 263A, 263B inthe rightward or leftward direction. As in the above describedembodiment, the bracket 262 can be fastened to the reinforcement portion166 by inserting a bolt 268 into the bolt insertion holes 264A, 265Bfrom below and threadingly engaging the bolt 268 with the bolt insertionhole 167. As in the above described embodiment, in the present modifiedexample, a spacer may be interposed between the reinforcement portionand the down frame. As shown in FIG. 13, the bracket 262 may have acantilever structure in which only the second bracket member is fastenedto the reinforcement portion.

Numeral modifications and alternative embodiments of the presentinvention will be apparent to those skilled in the art in view of theforegoing description. Accordingly, the description is to be construedas illustrative only, and is provided for the purpose of teaching thoseskilled in the art the best mode of carrying out the invention. Thedetails of the structure and/or function may be varied substantiallywithout departing from the spirit of the invention.

Hereinafter, the embodiment of the present invention will becomplementally described and modified examples will be described whilerepeating part of the description of the above components.

The present invention is not limited to the motorcycle, but isapplicable to any vehicle so long as it is a straddle electric vehicleor an electric vehicle including a bar-type handle. Especially, thepresent invention is suitably applicable to a vehicle in which at leasta portion of a battery case is exposed to outside of the vehicle. Thepresent invention is not limited to a vehicle which does not include aninternal combustion engine, but is suitably applicable to a hybridvehicle in which a prime mover includes an electric motor and aninternal combustion engine. Furthermore, the present invention isapplicable to any vehicle incorporating a battery. Moreover, the batterycells may be a lithium ion battery, a nickel metal hydride, or a fuelcell.

The battery case has a portion which faces the ground surface in thevertical direction. The battery case is placed between the front wheeland the rear wheel. Water splash and the like from the wheels and theground surface tend to adhere to the case. However, with theconfiguration of the present invention, entry of liquid into the casecan be prevented. Since the entry of water from below into the case canbe suitably prevented, the battery case may be placed in a lowestpossible location and close to the ground surface. This can lower acenter of gravity.

Preferably, the vehicle components such as the motor case and theinverter case are placed in a location below the parting line of thebottom surface of the case, more preferably in a forward location belowthe parting line of the bottom surface of the case. This makes itpossible to prevent liquid scattered from the load surface or fromforward from approaching a region in the vicinity of the parting line.

The battery unit 60 is supported on the bottom surface of the batterycase 80. Specifically, the battery modules 61 are supported by thebattery frame 64 placed under the battery case 80. The weight of thebattery modules 61 is transferred to the battery frame 64 and the bottomsurface of the battery case 80 in this order. Since the lid member 84 isattached on the upper surface of the battery case 80, the parting lineis not exposed on the upper surface of the battery case 80. As describedabove, the rain water is less likely to be accumulated on the flat uppersurface of the lid member 84. If the rain water is accumulated on theupper surface of the battery case 80, the entry of the rain waterthrough a clearance of the parting line can be prevented.

The battery frame for integrating the battery modules, and the batterycase for shielding the battery modules from an outside space areseparate components. Since the component for integration and thecomponent for sealing are implemented by different components, thebattery frame is allowed to have a non-sealed shape like the frame shapeand therefore have a reduced weight. The battery case may be made of amaterial which is lower in strength than the battery frame. Thus, anundesired increase in a stiffness can be avoided, and a reduced weightof the battery case can be achieved. Furthermore, the battery modulesintegrated by the battery frame are stored into the battery case easilywhile reducing a gap between the battery modules and the battery case.

The air-intake duct extends upward in a rearward direction and isconnected to the battery case, at a portion connected to the batterycase. This makes it possible to prevent the water droplets adhering tothe interior and exterior of the air-intake duct from entering thebattery case. A water drain hole may be formed in the lowermost portionof the air-intake duct. This can further reduce the water dropletsentering the battery case through the air-intake duct.

The battery case may be made of a composite material such asfiber-reinforced plastic containing a material for improving astiffness, instead of the synthetic resin. The battery case may have astructure in which the lid is omitted, and may be constructed byseparably joining, for example, two cup-like case members. In this case,the body section of the first case member has, in a state in which thebattery case is incorporated into the vehicle, a bottom surface portion,front, left and right side surface portions extending upward from thebottom surface portion such that they are bent, and an upper surfaceportion, and opens rearward. The body section of the second case memberhas, in a state in which the battery case is incorporated into thevehicle, a bottom surface portion, rear, left and right side surfaceportions extending upward from the bottom surface portion such that theyare bent, and an upper surface portion, and opens forward.

The case body 81 may be dividable in the forward or rearward direction,or in the rightward or leftward direction. The bottom wall preferablyhas the parting line which may extend such that it is inclined in theforward or rearward direction, in the rightward or leftward direction orin the vertical direction with respect to at least one surface in whichthe parting line is formed. To prevent entry of the rain water,preferably, the separation is not formed in the front surface. In manystraddle vehicles, a vertical dimension and a dimension in the forwardor rearward direction are set greater than a dimension in a vehiclewidth direction. To realize an increase in a battery capacity under thecircumstances, a vertical dimension and a dimension in the forward orrearward direction of the battery case 80 are also set greater than adimension in the vehicle width direction. In this case, if the batterycase 80 is dividable into front and rear sections rather than right andleft sections and upper and lower sections, the whole length of theparting line becomes small, and thus a possibility of the entry of rainwater can be reduced.

The case body 81 may be dividable vertically instead of horizontally. Inthis case, it becomes possible to prevent rain water dropping from abovefrom entering the case. In this case, one of the two flanges mayprotrude outward of the case farther than the other, and may be orientedin a direction different from upward. In a case where the case body 81is dividable horizontally, the outer surface of the battery unit 60 canbe made close to the inner surface of the case according to verticaluneveness of the outer shape, even when the outer shape of the batteryunit 60 is made vertically uneven. For example, in a case where avertically intermediate portion of the battery unit has a plurality ofrecesses and the case is vertically dividable into upper and lowersections, a gap tends to be formed between the outer surface of therecess and the inner surface of the case, and hence the case tends beincreased in size. In the case of the case body which is horizontallydividable, the battery case may be formed to have recesses correspondingto the recesses of the battery unit, and an increase in the size of thecase can be avoided.

The flange section and the down frame are placed with a gap betweenthem, and a portion of the down frame is displaced downward to preventinterference between the flange section and the down frame. This makesit possible to prevent a stress from concentrating on the flangesection.

Support portions are placed at front and rear sides with the flangesections interposed between them. The battery case can be stablysupported at the front and rear sides. Since the battery frame extendsalong the frames when viewed from above and has a portion extending overthe front and rear buffer members in a state in which the battery frameis incorporated into the vehicle, it can transfer the weight of thebattery modules above the flange sections to the buffer members at frontand rear sides, which can prevent the load from being applied to theflange section. The buffer members may be fastened to the lower surfaceof the bottom portion of the frame or to the upper surface of the bottomportion of the case.

The down frames 13 may be removably mounted to the main frames 12. Forexample, the down frames 13 may be inserted into a space between thepair of main frames 12 together with the battery case 80.

The battery case may be placed between the front and rear wheels, andforward relative to the seat. The rear portion of the battery case issmaller in dimension in the right and leftward direction than the frontportion of the battery case. Also, the upper portion of the battery caseis smaller in dimension in the right and leftward direction than thelower portion of the battery case. In the above described embodiment,the rear upper portion of the battery case is smaller in dimension inthe right and leftward direction than a portion in the vicinity of therear upper portion. This allows the battery case to be directly orindirectly retained by the knees of the rider straddling the vehiclebody. As a result, a storage region in the interior of the battery casecan be increased as much as possible, and hence the capacity of thebattery in the interior of the battery case can be increased, whileallowing the vehicle body to be retained easily by the rider.

The vehicle body includes a stand which allows the vehicle body to standfor itself in a state in which the vehicle body is inclined at one sidein the right and leftward direction during a stopped state of thevehicle. The battery case may be provided with a water drain hole in aportion which is in a lowest position in the state in which the vehiclebody is standing for itself such that it is inclined. For example, in acase where the stand is provided at a left side, the water drain hole isprovided in the left end portion of the bottom portion of the batterycase to discharge water or water droplets from the interior of the case.The water drain hole may have a labyrinth shape or may be attached witha cap which can open and close the water drain hole. With thisstructure, entry of the water into the case through the water drain holecan be prevented.

Regarding the electric wires extending from the battery case to theinverter, the wire harness 74 extending from the battery case andconnected to the inverter is provided with an insulative protectioncover covering the electric wires. In at least a region in the vicinityof the rider straddling the vehicle body, the wire harness extends in aspace between the protection cover and the battery case. In the presentembodiment, the protection cover is placed in at least a region in thevicinity of the rider's knees. The protection covers are placed at rightand left sides. The distance between the right and left protectioncovers, corresponding to the rear upper portion, is set smaller than thedistance between the right and left protection covers, corresponding tothe remaining portion. This allows the cover to be retained by the kneesof the rider straddling the vehicle body, and hence the vehicle body tobe easily retained by the rider. The rear surface of the protectioncover and the rear surface of the air discharge duct are coplanar witheach other in a location rearward relative to the battery case in therightward or leftward direction, and the seat is placed rearwardrelative to and below the rear surface of the protection cover and therear surface of the air discharge duct. This allows the rear surface ofthe protection cover and the rear surface of the air discharge duct toserve as a wall for inhibiting the rider straddling the seat from beingdisplaced forward. In addition, by making the rear surface of theprotection cover and the rear surface of the air discharge duct coplanarwith each other, the duct can be increased in size, and the battery canbe cooled more effectively.

Although in the above described embodiment, the storage section forstoring the ECU is provided outside of the battery case, it may beprovided inside of the battery case. This makes it possible to preventthe ECU from being detached undesirably. Thus, an anti-theft functioncan be improved. Or, in a case where an ECU for controlling the motorand an ECU for controlling the battery are separate components, abalance of the vehicle body in the rightward or leftward direction canbe improved by placing the ECUs at right and left sides of the batterycase. Or, the ECU for controlling the battery may be placed inside ofthe case and the ECU for controlling the motor may be placed outside ofthe battery. In this case, the ECU inside of the battery case preferablycontains a control program for inhibiting the vehicle body from movingunless a correct key is used.

In a case where a fastening member (e.g., bolt 133) for fastening thecase members of the battery case is used, at least the surface of thefastening member is preferably made of an insulating material. In thepresent embodiment, the fastening member for fastening the lid memberprovided at the upper portion of the battery case is made of aninsulating material. This can reduce a possibility that a short circuitof an electric circuit is formed inside of the case even if thefastening member falls down into the case.

The air inlet 111 of the battery case may be provided with an airfilter. This makes it possible to prevent ingress of foreign mattersinto the case. The air-intake duct extends from a front cowling (notshown) and is connected to the battery case through one side in therightward or leftward direction relative to the heat pipe. The electricwires used to transmit signals and electric power to meters and the likeextend through the other side in the rightward or leftward directionrelative to the head pipe. Since the duct is placed at the sidedifferent from the side where the electric wires are placed, easyrouting of the duct can be implemented.

Cleaned air in the interior of the case may be guided to the inverter tocool the inverter. Especially, by flowing the air along the boardsurface of the inverter, rust of the board surface can be prevented. Forexample, by using a liquid cooling medium for cooling IGBT elements, ora gaseous cooling medium for cooling the board surface of the inverter,the cooling of the inverter can be promoted.

Since the DC/DC converter is stored in the case, the converter which isa high-voltage device is not exposed to outside. In the same manner, theDC/DC converter relay, the charging relay, the main relay, etc., areplaced in the interior of the case.

The motor is placed below the battery support frame and the batterysupport frame supports the motor. A portion or front portion of the downframe serving as the support frame for supporting the battery may beremovably joined to the remaining portion of the vehicle body frame 4.

The lower portion of the battery support frame is removably attached tothe remaining portion of the battery support frame by the fasteningmember. In a state in which the lower portion of the battery frame, thebattery case and the battery are unitarily fastened to each other, theremaining frame members are placed from above. In other words, thebattery case is inserted from below the remaining frame members. In thisstate, the battery frame is lifted by a hook, and the remaining framemembers and the frame are connected to each other, thereby allowing thebattery to be supported on the vehicle body frame.

Since the lower portion of the battery frame, the battery case and thebattery are unitarily fastened to each other, the lower portion of theframe can bear the weight of the battery even in an upper body detachedfrom the remaining frame members. Therefore, it is not necessary toincrease a stiffness of the frames in excess.

Furthermore, an air guide path leading to the case may be formed withinthe support frame. The suspending member for supporting the batteryframe may be removably mounted to the battery frame. The suspendingmember may be mounted to the battery frame during maintenance and may bedetached from the battery frame when the battery case is mounted to thevehicle body.

INDUSTRIAL APPLICABILITY

The present invention has advantages that the battery can be easilyremovably mounted to the case and the case can have a high stiffness,and is effectively applied to straddle electric vehicles, especiallylarge electric motorcycles which are able to generate great drivingpower.

REFERENCE CHARACTERS LIST

-   -   1 electric motorcycle    -   2 front wheel    -   3 rear wheel    -   4 vehicle body frame    -   5 electric motor    -   20 inverter    -   30 inside electric component    -   31 high-voltage electric wire    -   55 exhaust fan    -   60 battery unit    -   61 battery module    -   64 battery frame    -   74 wire harness    -   80 battery case    -   81 case body    -   82 opening    -   83 upper lid    -   111 first case member    -   112 second case member    -   113 first body section    -   114 first flange section    -   115 second body section    -   116 second flange section    -   117 first case joining section    -   118 second case joining section    -   121 first outward protruding portion    -   122 rearward protruding portion    -   140, 145 positioning sections    -   150 battery fastening section

The invention claimed is:
 1. A straddle electric vehicle which rotates adrive wheel by driving power generated in an electric motor, comprising:a battery unit which is an electric power supply for the electric motor;and a battery case for storing the battery unit; wherein the batterycase includes a pair of case members including a first case member and asecond case member which are joined together such that the first casemember and the second case member are separable from each other, and aparting line of the first case member and the second case member extendson a bottom wall of the battery case; wherein the bottom wall of thebattery case includes a bottom wall of the first case member and abottom wall of the second case member such that the parting line is aboundary between the bottom wall of the first case member and the bottomwall of the second case member; and wherein the first case member andthe second case member include a first flange section and a secondflange section, respectively, which define the parting line, andprotrude outward of the battery case, the first case member and thesecond case member being separably joined to each other in a state inwhich the first flange section and the second flange section are engagedwith each other.
 2. The straddle electric vehicle according to claim 1,wherein one of the first flange section and the second flange section isexposed outward of the battery case farther than the other of the firstflange section and the second flange section and is oriented in adirection different from forward.
 3. The straddle electric vehicleaccording to claim 1, comprising: a battery fastening section forfastening the battery unit to the battery case; wherein the batteryfastening section is placed in an inner space of the battery case. 4.The straddle electric vehicle according to claim 1, comprising: a casejoining section for joining the first case member to the second casemember; and wherein the case joining section is provided on an outersurface of the battery case.
 5. The straddle electric vehicle accordingto claim 1, wherein the first case member and the second case member arejoined together such that the first case member and the second casemember are separable from each other in a forward or rearward direction,and the first case member is placed forward relative to the second casemember; and wherein the first flange section includes an outwardprotruding portion which protrudes outward of the case farther than theremaining portion of the battery case and a rearward protruding portionextending rearward from the outward protruding portion; and wherein therearward protruding portion is located outward of the case relative tothe second flange section and is oriented rearward.
 6. The straddleelectric vehicle according to claim 1, comprising: an inside electriccomponent stored in the battery case; an outside electric componentdisposed outside of the battery case; and an electric wire electricallyconnecting the battery unit or the inside electric component to theoutside electric component; wherein the electric wire extends from arear surface of the battery case to the outside electric component. 7.The straddle electric vehicle according to claim 6, wherein the batterycase has an upper lid which is removably attached on an upper portionthereof; and wherein the inside electric component is placed in an upperportion in an interior of the battery case.
 8. The straddle electricvehicle according to claim 1, wherein the parting line extendshorizontally on the bottom wall.
 9. The straddle electric vehicleaccording to claim 1, wherein the parting line is provided in a centerportion of the bottom wall.
 10. The straddle electric vehicle accordingto claim 1, wherein the parting line is provided within a verticalplane.
 11. The straddle electric vehicle according to claim 1, whereinthe first case member and the second case member are joined togethersuch that the first case member and the second case member are separablefrom each other in a forward and rearward direction or in a rightward orleftward direction.
 12. A straddle electric vehicle, which rotates adrive wheel by driving power generated in an electric motor, comprising:a battery unit which is an electric power supply for the electric motor;and a battery case for storing the battery unit; wherein the batterycase includes a pair of case members including a first case member and asecond case member which are joined together such that the first casemember and the second case member are separable from each other, and aparting line of the first case member and the second case member extendson a bottom wall of the battery case; wherein the bottom wall of thebattery case includes a bottom wall of the first case member and abottom wall of the second case member such that the parting line is aboundary between the bottom wall of the first case member and the bottomwall of the second case member; and wherein the first case member andthe second case member includes a first flange section and a secondflange section, respectively, which define the parting line, and areseparably joined to each other in a state in which the first flangesection and the second flange section are engaged with each other, andthe straddle electric vehicle further comprising: a front wheel and arear wheel which are placed such that the battery case is interposedbetween the front wheel and the rear wheel in a forward or rearwarddirection; and an exhaust fan for exhausting air from an interior of thebattery case; wherein the exhaust fan is placed at an upper portion ofthe battery case.
 13. A straddle electric vehicle which rotates a drivewheel by driving power generated in an electric motor, comprising: abattery unit which is an electric power supply for the electric motor;and a battery case for storing the battery unit; wherein the batterycase includes a pair of case members including a first case member and asecond case member which are joined together such that the first casemember and the second case member are horizontally separable from eachother, and a parting line of the first case member and the second casemember extends along a bottom wall of the battery case; and wherein thefirst case member and the second case member include a first flangesection and a second flange section, respectively, which define theparting line, and protrude outward of the battery case, the first casemember and the second case member being separably joined to each otherin a state in which the first flange section and the second flangesection are engaged with each other.